Chapter Three:


by Lawrence W. Sherman

..many community characteristics implicated in violence, such as residential instability, concentration of poor, female-headed households with children, multiunit housing projects, and disrupted social networks, appear to stem rather directly from planned governmental policies at local, state and federal levels.

--National Academy of Sciences report, 19931

Communities are the central institution for crime prevention, the stage on which all other institutions perform. Families, schools, labor markets, retail establishments, police and corrections must all confront the consequences of community life. Much of the success or failure of these other institutions is affected by the community context in which they operate. Our nation's ability to prevent serious violent crime may depend heavily on our ability to help reshape community life, at least in our most troubled communities. Our good fortune is that the number of those troubled communities is relatively small. Our challenge is that their problems are so profound.

Serious violent crime is not a problem for most residential communities in the United States. In the suburban areas where most Americans live, the homicide rate is comparable to Finland's (FBI, 1994: 191; Reiss and Roth, 1993: 52). Half of all American homicides occur in the 63 largest cities, which only house 16% of the U.S. population. Homicides in those cities are also highly concentrated, in a handful of communities marked by concentrated poverty, hypersegregation (Massey and Denton, 1993), family disruption and high gun density. Almost 4% of all homicides in America involve gang members in Los Angeles County alone (Klein, 1995: 120). Serious violent crime in America is predominantly a matter of one particular kind of community, increasingly isolated and shunned by the rest of American society (Wilson, 1996).

The causation of inner-city crime has received extensive diagnosis (Wilson, 1987, 1996; Massey and Denton, 1993; Bursik and Grasmik, 1993; Sampson and Lauritsen, 1993). The prevention of inner-city crime has been attempted with extensive programs. The connection between causes and prevention, however, has been weak at best, and often nonexistent. More than any of the other institutional settings, the community setting shows a striking divergence of causal analysis and prevention programs. The causes, or at least the risk factors correlated with serious crime,2 are basic and interconnected, while the programs are superficial and piecemeal. Federal policies from urban renewal to public housing may have done more to cause inner city violence than to prevent it (Sampson and Lauritsen, 1993: 89). For most of this century, community crime prevention programs have failed to tackle the governmental policies and market forces that fuel inner-city violence.

A central issue in the disconnection between causes and cures is the assumptions of how these communities "got that way." As William Julius Wilson has observed, "The segregated ghetto is not the result of voluntary or positive decisions on the part of the residents... [but is] the product of systematic racial practices such as restrictive covenants, redlining by banks and insurance companies, zoning, panic peddling by real estate agents, and the creation of massive public housing projects in low-income areas." The result of these forces in recent years has been called "hypersegregation:" historically unprecedented levels of geographic segregation by race and class, magnifying the effects of poverty and racial isolation (Massey and Denton, 1993). Yet community prevention programs address none of these causes of community composition and structure, which in turn influence community culture and the availability of criminogenic substances like guns and drugs.

Ironically, a central tenet of community prevention programs has been the empowerment of local community leaders to design and implement their own crime prevention strategies. This philosophy may amount to throwing people overboard and then letting them design their own life preserver. The scientific literature shows that the policies and market forces causing criminogenic community structures and cultures are beyond the control of neighborhood residents, and that "empowerment" does not include the power to change those policies (Hope, 1995). It is one thing, for example, for tenants to manage the security guards in a public housing project. It is another thing entirely to let tenants design a new public housing policy and determine where in a metropolitan area households with public housing support will live.

Even the management of modest programs with federal support are often beyond the capacity of community organizations, especially where it is needed the most. The consistent evidence of the neighborhood watch programs, for example (Skogan, 1990: chapter 6), is that the more crime and risk factors a neighborhood suffers, the less likely it is to develop any organized activity to fight crime. When community organizations do get involved in administering federal funds, there are often major problems and scandals of financial mismanagement. "Empowering" local communities with federal funding often turns into no applications from the worst areas and red tape nightmares for the not-so-bad areas that do get involved.

The disconnection between causation and prevention is also clear in the official use of the term "comprehensive." To be comprehensive in addressing risk factors is very different from being comprehensive in mobilizing all available agencies of government. Recent "comprehensive" crime prevention programs merit the term more by agency participation than by risk factors. The fit between agencies and risk factors is good in a few cases, such as home nurse visitation to address single parent childraising practices (see Chapter 4). But many risk factors have no obvious agency to fix them. Even multi-agency coordination is no guarantee that the major risk factors, like hypersegregation and labor market isolation (see Chapter 6), will be addressed.

Thus the major causes of community crime problems are like handcuffs locking a community into a high crime rate. The most frequently evaluated community-based crime prevention programs do not attempt to break those handcuffs. Rather, they operate inside those constraints, attempting "small wins" within the limited range of risk factors they can manipulate. But until the handcuffs of race-based politics themselves are unlocked, many analysts expect relatively little major improvements from programs addressing only the symptoms of those constraints.

Given the disconnection between causes and cures, it is not surprising that program impact evaluations provide little strong evidence of effective crime prevention. Setting aside programs delivered in families, schools, labor markets, places or the criminal justice system, the number of evaluations of community-based programs is quite small and generally discouraging. While there have been some "small wins," like reduced vandalism and drug use in housing projects with recreational programs, there have been no scientifically documented "big wins" preventing violence in a concentrated urban poverty area. Within that context, community mobilization efforts, gang prevention programs, gun buybacks, social worker and recreation programs have generally failed to show much if any effect on crime.

Yet the evaluation methods for these programs have generally been quite weak, and there is no certainty that such programs are doomed to failure even though they sidestep the central causes reflected in the scientific literature. Amidst generally negative results from generally weak program evaluations, there are encouraging findings from some research that may merit further testing, even though other studies have found contradictory results:

o Gang violence prevention has been effective in several case studies

o Community-Based Mentoring prevented drug abuse in one rigorous experiment

o Afterschool Recreation programs have reduced vandalism in public housing

These findings about community-based programs addressing "proximate" rather than "root" causes suggest a strategy for developing national crime prevention policy. Both the Justice Department and the rest of the federal government are moving towards concentration of resources on high-crime inner-city areas, which one-third of all African-Americans reside (Massey and Denton, 1993: 77) and where community factors generate the high homicide victimization rate of young black males--which is twelve times higher than the average in the US population (Fingerhut and Kleinman, 1990). Whether the efforts now in planning can address the structural factors is an unanswered question. But a combination of programs addressing proximate causes and the structural factors may have the best chance of success.

It is also possible that the diagnosis of community crime causation is incomplete. Even in the face of profound urban problems, it may be possible to reduce substantially the level of serious crime. New York City homicides and shootings dropped in half in recent years, with no documented change in concentrated urban poverty. It is not clear how or why that reduction occurred. The leading theory is the application of the police methods found effective in the studies reviewed in Chapter Eight. No community-level prevention program (or demographic change) has emerged as an alternative, competing explanation. But it remains possible to design such a program, focused more on the proximate than on the root causes of serious violence, and to test it in a randomized trial on a large multi-city sample of urban poverty areas. Programs currently planned by the executive branch to improve inner-city conditions can be most beneficial if they are structured to allow such a rigorous evaluation, so the nation can be very clear about the precise effects of the program on crime.

This chapter compares scientific evidence about community risk factors for violent crime to the logic of community crime prevention programs. It briefly reviews some methodological issues in evaluating those programs. It then examines the limited impact evaluations of crime prevention programs based in community settings outside the institutions examined in the next six Chapters. The chapter concludes by comparing the science of community-based crime prevention to major DOJ funding programs, with policy recommendations for both programs and research.


The science of crime causation, while still in its infancy, offers more than a century of research on the community characteristics associated with higher risks of violent crime (Quetelet, 1842). By "community," this literature usually denotes residential areas of varying size within cities. These areas may be as small as blocks (Taylor and Gottfredson, 1986) or cover several square miles (Shaw and McKay, 1942). Much of this literature, recently reviewed for an NIJ-funded National Academy of Sciences Panel (Sampson and Lauritsen, 1993), uses rates of homicide and other serious violent crimes as the major focus.

One framework for classifying community risk factors distinguishes community composition, social structure, oppositional culture, legitimate opportunities, and social and physical disorder. Each of these apparent risk factors could be the focus of comprehensive community crime prevention programs. Most are not. Instead, as the National Academy of Sciences report suggests, "non-crime" government policies may have done more over the past four decades to enhance these risk factors than to reduce them. Perhaps the most visible example is the construction of public housing projects (Bursik, 1989), which in one study was followed by increased population turnover and increased crime rates independent of race.

Community composition refers to the kinds of people who live in a community. Unmarried or divorced adult males, teenage males, non-working adults, poor people, persons with criminal histories and single parents have all been identified in the literature as the kind of people whose presence is associated with higher rates of violent crime (Messner and Tardiff, 1986; Sampson, 1986; Curry and Spergel, 1988; Bursik and Grasmik, 1993). What is unclear in the literature is whether having more such people simply produces a higher total of individual level risk factors, or whether there is a "tipping" effect associated with the concentrations of such people (Sampson and Lauritsen, 1993). The latter theory derives from substantial findings on the effects of proportions in groups and corporations (Kanter, 1977): in which behavior of entire communities changes when a proportion of one type of person goes beyond the tipping point.

Public policies contributing to the concentration of high-risk people in certain neighborhoods include the federally funded highway system that took low-risk people out of urban neighborhoods to the suburbs (Skogan, 1986). The suburbanization of both white middle class people through highways, and black middle class people through federal open-housing laws (Wilson, 1987), helped tip the proportions of many inner city communities towards a majority of persons or families at higher risk of crime. As long as those high-risk families or persons were in a minority, their low risk neighbors were able to exercise a community protective factor against violent crime. When the high-risk families became a majority in many urban communities, a spiral of crime and the fear of crime led to further loss of middle class residents and jobs. This in turn increased the concentration of unemployed and poor people, followed by further increases in crime (Schuerman and Kobrin, 1986; Wilson, 1996.) No federal or local public policies have yet to counteract, or even challenge, these proportional imbalances.

Community Social Structure. Independently of the kinds of people who live in a community, the way in which they interact may affect the risk of violent crime. Children of single parents, for example, may not be at greater risk of crime because of their family structure. But a community with a high percentage of single parent households may put all its children at greater risk of delinquency by reducing the capacity of a community to maintain adult networks of informal control of children. The greater difficulty of single parent families in supervising young males is multiplied by the association of young males with other unsupervised young males, since delinquency is well-known to be a group phenomenon (Reiss, 1988). The empirical evidence for this risk factor is particularly strong, with violent victimization rates up to three times higher among neighborhoods of high family disruption compared to low levels, regardless of other characteristics such as poverty, and the correlation between race and violent crime at the neighborhood level disappears after controlling the percentage of female-headed households (see Sampson and Lauritsen, 1993).

Other aspects of community structure include the prevalence of unsupervised male teenage groups, the density (or extent of overlap) among local friendship networks, and local participation in formal voluntary associations. Support for the inverse correlation of violent crime with voluntary association membership has been found at the block level in Baltimore (Taylor et al, 1984). Sampson and Groves (1989) found support for dense friendship networks as a protective factor and unsupervised teen groups as a risk factor for violence in the British Crime Survey. All of the risk factors have arguably been concentrated in urban neighborhoods by public policies. Skogan (1986) reviews the evidence on urban renewal's destruction of dense local friendship networks, uprooting entire neighborhoods; nationwide, 20 percent of all urban housing units occupied by blacks were demolished during the 1970s (Logan and Molotch, 1987: 114, as cited in Sampson and Lauritsen, 1993: 88). Wilson (1987) and Massey and Denton (1993) trace the history of public housing policy decisions that concentrated poor, black, female-headed households in limited areas rather than dispersing them amidst other kinds of families (Lemann, 1991). While community mobilization programs are designed in part to build voluntary association membership and increase informal social control, the evidence to date suggests that such efforts have not succeeded (Hope, 1995).

Oppositional Culture. Observers of high crime neighborhoods have long identified the pattern of "oppositional culture" arising from a lack of participation in mainstream economic and social life: bad becomes good and good becomes bad. Given the apparent rejection of community members by the larger society, the community members reject the values and aspirations of that society by developing an "oppositional identity" (Cohen, 1955; Clark, 1965; Braithwaite, 1989; Massey and Denton, 1993: 167). This is especially notable in terms of values that oppose the protective factors of marriage and family, education, work and obedience to the law. As inner-city labor force participation rates have declined (Wilson, 1996) and inner-city segregation has increased over the past three decades (Massey and Denton, 1993), the strength of the opposition has increased. Ethnographic studies of such cultures in recent years (e.g., Anderson, 1990) show more intense opposition than similar studies in the 1960s and 1970s (e.g., Liebow, 1967; Anderson, 1978), which found more widespread acceptance of mainstream values. Efforts to gain "respect" in oppositional cultures may then rely more on violence than on other factors (Anderson, 1990). Public policy has contributed to this primarily by its historical support for segregation and its modern failure to prevent its inner-city concentration, both by race (Massey and Denton, 1993: chapter 7) and joblessness (Wilson, 1996: chapter 3).

Criminogenic Commodities. Communities with very high rates of youth violence are places in which there are high concentrations of criminogenic commodities (Cook and Moore, 1995). Both alcohol use (Collins, 1989) and drug use (Goldstein, 1989) are highly correlated with violent crime at the situational level of analysis (Miczek, et al, 1993), and gun use in crime generally causes greater risk of homicide (Cook, 1991; Reiss and Roth, 1993). Other evidence suggests that high crime communities appear to have very high concentrations of locations selling alcohol (Roncek and Maier, 1991) and drugs (Sherman and Rogan, 1995). Whether the disproportionate presence of these substances reflects market demand arising from oppositional culture or other reasons (including public policy) is an unresolved issue in the literature.

Social and Physical Disorder. Recent work on the "broken windows" (Wilson and Kelling, 1982; Kelling and Coles, 1996) theory of community crime causation suggests some support for the theory (Skogan, 1990). The theory claims that in communities where both people and buildings appear disorderly, the visual message that the community is out of control may attract more serious crime (Wilson and Kelling, 1982). This may happen by a spiral of increasing fear of crime among conventional people, who use the area less and thus provide less informal control. Communities that deteriorate in this respect over time are observed to suffer increased rates of violence (Schuerman and Kobrin, 1986). Public policies contribute to such declines through nonenforcement of building code violations (Hirsch, 1983) and of minor criminal conduct such as public drinking (Kelling and Coles, 1996). Demolition policies to reduce the unsightly appearance of decayed buildings may then also reduce neighborhood density of street populations, the effect of which is not clear in the literature; lower density may either increase the risk of violent crime (Wilson, 1996) or reduce it (Sampson and Lauritsen, 1993).

All of these risk factors and more are connected to broader debates about race, poverty, welfare, unemployment and family life in America. These debates often ignore the extreme inner-city concentrations of these risk factors. These concentrations are both extreme in each category and in their accumulation. Few neighborhoods in the US suffer nonemployment rates as high as 63 to 77 percent of all adults. The ones that do are also likely to suffer from weak social structure, high rates of alcohol abuse, gun carrying, drug abuse, and violent youth crime. To the extent that policy debates focus on these issues outside of the inner-city areas of concentration, it may fail to attack the interdependence between these risk factors.


In order to learn whether federal policies can at least reduce violent crime in such communities, both strong programs and strong scientific methods should help. In this context, "strong" programs would address multiple risk factors simultaneously, while "strong" scientific methods would isolate the separate effects of different program elements. Using these definitions, the current state of the science offers no strong tests of strong community crime prevention programs.

The evaluations reviewed in this chapter generally employ weak research designs to test programs focused on symptoms of community risk factors, rather than the basic risk factors themselves. This limits our ability to draw conclusions about what effects, if any, the evaluated programs really have. As Chapter Two explains, all evaluations are not created equal. Some of them provide far stronger evidence about cause and effect than others. The strong ones generally employ large samples, reliable measures of both program operations and their intended effects, and possible rival causes of those effects. The weaker ones, quite common in this chapter, may measure program content and crime, but do a very poor job of measuring other factors that may affect crime besides the program.

This chapter uses the scale of scientific methods scores presented in Chapter 2. On a scale of 1 to 5, each specific evaluation reviewed is ranked for its capacity to support strong conclusions about the effect of the program. This strength of evidence is often unrelated to costs, or even the theoretical strength of the program being tested. The massive Chicago gang prevention project of the early 1960s, for example, gathered detailed records on thousands of interactions between the gang workers and area youths. But because the program area was the unit of analysis, not those interactions, the actual sample size was only 4 areas, and the power to infer cause and effect was quite low. Any number of other factors could have caused crime in those areas to go up or down besides the presence or absence of the intensively measured gang prevention programs.

This problem poses a serious obstacle to advancing scientific knowledge about community-based crime prevention. Community risk factors can only be addressed and measured one community at a time. The cost of measuring some factors is very high. Multiplying that cost across a substantial sample of communities has long been deemed prohibitive by research funding agencies. Yet the cost of inner-city violence is also very high. The cost of more rigorous program research could be well justified if it led to more effective community-based prevention programs. In the absence of such investment to date, however, there is not a single large-sample randomized controlled trial in which the community is the unit of analysis and the outcome measure is serious crime.

A related problem of scientific method is the simultaneous application of more than one program to a community at a time. These combinations of treatments are usually premised on the rationale that the more programs, the better: comprehensively attacking many risk factors at once should increase the overall chances of successful crime prevention. In the words of one observer, the theory is that "only everything works." The problem is that even with successful results, a combination of programs makes it impossible as a matter of scientific method to isolate the active ingredients causing the success. It may be all of them in combination. Or it may be only one or two.

A third related issue is the choice of program elements. Many funding programs leave the choice of specific prevention programs up to local communities. Local assessment of specific community risk factors and local decisions about program content are a key part of many community-based strategies (Hawkins, et al, 1995). But from a scientific standpoint, the variability in these combinations across communities allows an evaluation to test the effects of the general strategy, and not the specific program elements. Research designs in other fields have been used to systematically vary the program combinations, and determine across large samples which combinations are most effective, holding other factors constant through random assignment. This approach, or some variant of it, can be used in evaluating community programs, and may be implemented soon in England (Farrington, 1997).

There is no necessary tradeoff, as some have suggested, between comprehensive programs and scientific evaluations. While the operational and research problems in multi-community designs are clearly complex, they can be addressed with sufficient time and resources. As recent DOJ crime prevention policy has moved in the direction of comprehensive community programs, both the number of treatments and the number of communities have become increasingly critical aspects of the potential return on evaluation dollars. The scientific solution to the methodological limitations observed so far is larger sample sizes, with varying combinations of the treatments. The best argument in favor of this "big science" solution is the evidence that follows, and the extremely limited conclusions we can draw from the $100 million or more (in current dollars) of private and public funds that it cost over the past three decades to conduct the studies examined below.


The most visible community-based crime prevention strategy in the latter Twentieth Century has been community mobilization. The definition of this term has varied widely, from the creation of formal community development organizations to the mobilization of resources from outside the community to help solve local problems like crime and unemployment. Hope's (1995) review of the evaluations of these programs finds virtually no evidence that the programs attempted to date have achieved an impact on crime. In some cases, as in New York City's Mobilization for Youth Project of the 1960s, that is due to the lack of crime impact evaluations. In other cases, it is due to a failure to implement successfully the programs selected by community leadership to a degree sufficient to test the theory of the program. Whether the approach could be successful under conditions other than those evaluated to date remains unknown.

The Eisenhower Foundation's support of nonprofit community organizations in ten low-income neighborhoods in the late 1980s offers one of the best evaluations available (Scientific Methods Score = 3; Lavrakas and Bennett, 1989, as cited in Hope, 1995: 39-40). Its most encouraging finding is that eight of the ten sites actually implemented programs chosen during the planning process. This stands in strong contrast to the police-generated neighborhood watch programs reviewed in Chapter Eight, for which the major problem in low-income areas has been successfully organizing block or apartment house meetings of neighborhood residents. The Eisenhower site programs that were implemented ranged from individual-level social service provision to attempts to change community social structure. The evaluators concluded from the impact evaluations that there was "little evidence that the ...Program had documentable successes in achieving its major goals of crime reduction and improved quality of life."

These results may stem in part from what Hope (1995) calls the difference between "vertical" and "horizontal" strategies of community crime prevention. Horizontal strategies focus on aspects of community life and place accountability on community members to solve their own problems. Vertical solutions focus on the linkages between community life and decisions made at higher levels of power outside the community, from factory closings to bank redlining of mortgages. Recent scholarly analyses of community crime causes (e.g., Wilson, 1996) focus more on vertically determined dimensions of community life, while few prevention programs evaluated to date have drawn heavily on a vertical approach. Uses of vertical solutions to date have been relatively limited, such as seeking external assistance in street closings, assigning more police, and other city government decisions that leave untouched most of the risk factors cited above. But even local government decisions may make a difference.

In the NIJ-sponsored Hartford experiment in the early 1970s (Fowler and Mangione, 1986), the community mobilization of a resident organization was successful at street closing and obtaining increased police activity. Initial reductions in crime, however, were followed by increases in the third and fourth years of the program. This scientifically weak (Scientific Methods Score = 2) evaluation lacked a comparison area, which limits the interpretation of the target area crime trends. But it is of interest that in the two years after local police activity was reduced, resident mobilization rose to its highest program levels. But despite the peak level of community mobilization, robbery and burglary rose to their highest levels in the life of the project.

It may be that mobilization alone cannot bear down directly on crime, and that the "horizontal" theory of community crime prevention is not likely to succeed. Further experimentation with different "vertical" tactics may be needed to find out if community mobilization or other methods to affect decisions external to the local community can change such decisions in ways that cause local crime prevention.


The disconnection between causes and cures in community crime prevention is illustrated by our nation's approach to gang violence. Five recent reviews of this literature provide the evidence for this analysis (Klein, 1995; Spergel, 1995; Howell, 1995, forthcoming; Thornberry, forthcoming). Taken together, this research suggests four major conclusions:

1. Most government and private programs for gang prevention have been left unevaluated.

2. The few evaluated programs have either failed to decrease gang violencee, or have actually increased it.

3. Gang prevention programs have ignored the most likely causes of the recent growth of gangs, the community structure of growing urban poverty ghettoes.

4. Nonetheless, successful methods for preventing gang violence have been demonstrated in case studies, and could be subjected to controlled testing on a larger scale.

This section reviews the connection between gang membership and serious violent crime, the evidence on the causes of gang membership, and the evaluations of community-based programs for preventing gang violence. It concludes that while most evaluations have been negative, the scientific rigor of the studies has been weak. The case studies demonstrating success in preventing gang violence can be tested with much greater scientific rigor as possible national models. The high concentration of serious juvenile violence among gang members provides ample justification for large-scale research and development.

Gang Membership and Serious Crime

The basic question about gang prevention is whether it would have any impact on serious and violent crime. Success at gang prevention is only important to communities if eliminating gangs would reduce the number of serious crimes. The answer to that question has not been clear from the scientific evidence. Fortunately, a substantial investment in research by the U.S. Department of Justice Office of Justice Programs (OJP) has recently provided strong scientific evidence on the question. The Office of Juvenile Justice and Delinquency Prevention (OJJDP) Study Group on Serious, Violent and Chronic Juvenile Offenders shared with the University of Maryland Crime Prevention Project its draft report, one chapter of which reviews this evidence (Thornberry, forthcoming). The chapter examines longitudinal data on the connection between gang membership and serious crime in two birth cohort studies. It breaks the question into two parts:

o How much serious crime is committed by gang members?

o Does gang membership make any difference in the harm caused by the people who join gangs, or would they have committed the same amount of serious crime even without joining a gang? That is, do gangs facilitate serious crime, or merely recruit serious criminals?

Thornberry reports that in Rochester, NY, one-third of a panel of adolescent males reported being a member of a gang at some point before the end of high school. That same one-third committed 90 percent of the serious crimes in the entire panel, including 80% of violent crimes and 83% of drug sales. Thornberry also summarizes similar results from the NIH Center for Substance Abuse Prevention (CSAP)-funded study of gang members in the Seattle Social Development Project (Battin, Hill, Hawkins, Catalano, and Abbott, 1996, as cited in Thornberry, forthcoming). Gang members in Seattle comprised only 15% of the sample, but accounted for 85% of all robberies committed during grades 7 to 12, and 62% of all drug selling. Thornberry reports lower gang contributions for gang crime in Denver from Esbensen and Huizinga's (1993) panel data: with 6% of respondents reporting gang membership, gang members reported 35% of serious offenses and 42% of drug sales.

The hypothesis that gangs cause juveniles to commit more serious crimes than they would commit anyway receives a rigorous test in the OJJDP Rochester Youth Study. Thornberry et al (1993, as cited in Thornberry, forthcoming) report that gang members commit crimes against persons twice as often while they are active members of gangs than before and after active membership. Similar patterns were found for crimes in general and drug use, but not for property offenses. Thornberry (forthcoming) reports that similar patterns were observed in the Seattle CSAP project, except that involvement in drug sales in Seattle remained elevated even after gang membership ended (Hill, Hawkins, Catalano, Kosterman, Abbott and Edwards, 1996, as cited in Thornberry, forthcoming). More recent analyses of the Rochester data also show drug sales, as well as gun carrying, persisting at elevated rates even after gang membership ends (Lizotte et al, 1996).

Large sample, multiple interview, longitudinal self-reported offending studies are the strongest evidence possible on these questions. The studies reported here do not necessarily reflect the effects of gang membership in the highest-crime areas of the very large cities where serious juvenile violence is most concentrated. But the available evidence is clear enough to establish gang membership as a community risk factor appropriate for preventive programs. There is also a scientific basis for distinguishing gangs from drugs as a cause of violence, since Klein (1995) finds far more gang homicides without a drug link than with one.

Successful prevention of gang membership for substantial portions of adolescent males might reduce their rates of serious crime. Even among gang members, interventions to divert them from gang violence could prevent many crimes. The question then becomes how prevention or diversion can be accomplished at the community level of intervention. As a matter of science, the logical starting point is to attack the causes of gang membership.

Causes of Gang Membership

At the individual level of analysis, the causes of gang membership appear little different from the causes of delinquency in general (Thornberry, forthcoming). While the cumulation of disadvantages in life is a risk factor for both delinquency and gang membership, it is not clear why in the same community, some boys join gangs and others do not (Spergel, 1995).

At the community level of analysis, however, the patterns are somewhat clearer. The key fact to be explained is why gangs have spread so rapidly--almost contagiously--over the past decade, from a few big cities to virtually all large and middle-sized cities and many smaller cities and towns. Klein (1995: 91) reports a 345% increase in the number of cities reporting violent gangs from 1961 (54 cities) to 1992 (766 cities). The 1995 National Youth Gang Survey found 2,000 jurisdictions reporting 23,000 gangs with some 665,000 members (Moore, 1996, in Howell, forthcoming). Within cities in which gangs have been well-established for decades, gang-related homicides have also risen dramatically, such as the 392% increase in Los Angeles County from 1982 to 1992 (Klein, 1995: 120). Klein (1995: 194) concludes that while the rise of homicides is partly driven by the growth in gun carrying, the growth of gangs themselves is strongly linked to the rapid growth of urban "underclass" areas.

Drawing heavily on William Julius Wilson's (1987) analysis of the new urban poverty ghettoes, Klein isolates five factors: the loss of industrial jobs, out-migration of middle-class blacks, growing residential segregation of inner-city blacks, increasing failure of schools to prepare inner-city children for a service economy, and the consequent strains on family life of the declining ratio of "marriageable" (that is, employed) males to females of child-bearing years. Hagedorn (1988) applies this theory to the case study of Milwaukee, and finds a good fit with the facts: gang membership and violence rose as the Wilson model of concentrated urban poverty developed in that city. Huff's (1989) comparison of gangs in Columbus and Cleveland found much more rapid growth in Cleveland, where the Wilson model had rapidly accelerated, than in Columbus, where community factors had remained fairly static. Jackson (1991) found across a large sample of cities that two factors predicted whether they developed gangs, job opportunities and the proportion of the population ages 15 to 24.

Klein's own work with Fagan (reported at Klein, 1995: 204) finds that 1970 Census data on community characteristics at the city level predict gang emergence in the 1980s. Specifically, racial segregation and a low proportion of persons in the labor force in 1970, although not concentration of poverty in 1970, predicts the 1980s emergence of gangs. So does an interaction of the loss of manufacturing jobs and unemployment rates. Different patterns are evident, however, for blacks and Hispanics, with strong effects for the former but not the latter. Curry and Spergel (1992) also report black-Hispanic differences in causes of gang growth, with more emphasis on cultural factors for Hispanics and structural factors for blacks. These findings lead Klein (1995: 205) to this conclusion about the design of gang prevention programs: "at least some portion of the gang proliferation problem is reflective of larger social ills. Merely addressing gang problems through gang intervention, be it street work or suppression, won't have much effect."

Evaluations of Gang Prevention Programs

The impact evaluation literature is largely consistent with Klein's conclusion. Howell's (1995, forthcoming) review of these data for OJJDP includes nine studies, from which "nothing has been demonstrated through rigorous evaluation to be effective in preventing or reducing serious and violent gang delinquency, [although] a number of promising strategies are available" (Howell, forthcoming, p. 21). Spergel's (1995: 256) independent review of the same evidence reaches the same conclusion: "traditional social intervention programs, whether agency-based, outreach or street work, or crisis intervention, have shown little effect or may even have worsened the youth gang problem."

Gang Membership Prevention. Three studies test a gang membership prevention program on a population of potential gang members. The first evaluation dates to the 1930s, when University of Chicago gang scholar Frederic Thrasher (1936, as cited in Howell, forthcoming) directed a four-year study of the "character-building" and recreation programs of a New York City Boys' Club. His conclusion sounds much like Klein's a half-century later: the program was unable to prevent gang membership due to family, school and poverty problems. "These influences for the most part were beyond the power of the Boys' Club to neutralize" (p. 78). The second study is a description of a grass-roots residential and nonresidential "sanctuary" from street life in Philadelphia (Woodson, 1981), without a comparison group. The House of Umoja also initiated "gang summits," so it is difficult to credit the city-wide drop from thirty-nine gang homicides in 1973 to one in 1977 to prevention alone.

The third prevention program (Thompson and Jason, 1988, as cited in Howell, forthcoming) consists of a gang prevention curriculum and afterschool recreational activities offered to eighth grade students suggests. The evaluation's conclusion that the program was successful is based on a difference of three more students who became gang members in the comparison group (4 out of 43) than in the experimental group (1 out of 74). The evaluation design also suffered substantial attrition between exposure to treatment and followup interview, as well as the common problem of school-based evaluations (see Chapter Five): the treatment was assigned at the level of the school, but evaluated at the level of the student. The design featured three pairs of schools, with one in each pair assigned to receive the program. The outcome data are not reported at the school level, but the base rate of gang membership in the short followup period renders most other aspects of the design less important. In sum, there is little empirical basis for promise in the Thompson and Jason (1988) evaluation of the gang prevention curriculum and afterschool program.

Gang Intervention. The programs for intervening with already active gangs and gang members are somewhat more rigorously evaluated. While the oldest and most influential of all gang intervention and prevention projects, the Chicago Area Project, has never been evaluated, its primary component has been evaluated several times. That component is the "detached worker," a trained youth counselor who spends most working hours on the streets with gang members. The role and function of these workers varies somewhat across projects, largely on a dimension of how much formal programming they organize, such as club meetings or outings to major league baseball games. Some detached workers also try to organize adults into voluntary associations, and to develop community-level capacity for leadership and problem-solving. The workers vary in the extent to which they focused on gangs as groups or on gang members as individuals. The common core of their role is an attempt to redirect gang energy towards legitimate activity, including school and work, as well as to discourage crime.

Despite these variations on the theme, none of the evaluations of detached worker programs found any evidence of reduced crime. Klein (1971), in fact, found just the opposite in an African-American area of Los Angeles: the detached workers increased the level of crime, which declined after the program was terminated. His explanation for that result is that the detached workers enhanced group cohesion, which in turn increased the "productivity" of the gang with its major product, crime. The theoretical significance of that conclusion is enormous, given the implications for other gang programs that may also increase cohesion. Durkheim's basic principle that group solidarity is increased by external attack would apply, for example, to police efforts to lock up a gang. Such a struggle with authorities can provide glory and meaning to otherwise barren lives, and simply encourage more violence.

In a followup study, Klein (1995: 146)) applied the group cohesion theory in an explicit attempt to minimize it. The Ladino Hills program tested a strategy of working only with 100 Hispanic gang members as individuals, not with the gangs as a group. Detached workers in this evaluation encouraged gang members to drop out of the gang, which some of them did as long as the workers were around; gang arrests declined 35% during that period. Gang cohesion also remained low for a six month followup period after the program ended. Several years after the program ended, Klein reports, gang cohesion and crime returned to its baseline levels. He concludes (1995: 147) that gangs "cannot long be controlled by attacks on symptoms alone; community structure and capacity must also be targeted."

Limited evidence against the cohesion hypothesis, however, comes from a California Youth Authority program in Los Angeles in the mid-1970s (Torres, 1981, cited in Klein, 1995: 149). Over four years, cohesion-building efforts with seven Hispanic gangs, including sports activities, served as a basis for truce meetings and feud mediation. Homicides and intergang violence declined among the targeted gangs, but not between targeted gangs and other groups. Klein (1995: 149) is skeptical about the reliability of the police data on "gang" crimes, but concludes that "further research attention to such intensive efforts as took place in this CYA project certainly seem warranted."

Table 3-1

Findings from Gang Prevention and Intervention Evaluations

(Secondary Sources: Howell 1995, forthcoming; Klein, 1995)

Primary Evaluation    Scientific Rigor      Program Content       Program Effects        

Gang Membership                                                                          

Thrasher 1936         ?                     NYC Boy's Club        No preventive effect   

Woodson 1981          2                     House of Umoja,       Gang Murders declined  

Thompson & Jason      2                     12 Gang Prevention    Major attrition,       
1988                                        Classes; some         small N joined gangs;  
                                            afterschool options   1 of 74                
                                                                  Experimentals, 4 of    
                                                                  43 Comparison          

Gang Member                                                                              

Miller 1962           3                     Goal: turn gangs      No effect on           
                                            into clubs, 7         delinquency measures   
                                            detached workers,     of targets             
                                            205 boys                                     

Gold & Mattick 1974   3                     Detached Workers      No effect on area      
cited in Spergel                            focused on gangs;     crime or gang crime;   
1995: 249                                   community             slight effect on       
                                            organization          educational goals      

Bibb 1967             ?                     NYC Detached Workers  No effect on gang      
                                            with gangs            crime                  

Klein 1969            2                     LA Group Guidance     Project increased      
                                            5 detached workers    delinquency; more      
                                            5 gangs, weekly       program, more crime;   
                                            meetings, program     crime reduced when     
                                                                  program ended          

Klein 1968,           2                     100 Ladino Hills      35% reduction in gang  
1995:145-147                                gang members          arrests from less      
                                            encouraged to leave   gang cohesion; effect  
                                            gangs, 18 months      lost after 2 yrs       

Torres 1981           2                     Older gang leaders    Homicides and          
                                            hired as              intergang violence     
                                            consultants, truces   declined among target  
                                            and feud mediation    gangs, not other       

Spergel 1986          3                     Crisis intervention   Less serious crime     
                                            & mediation by        for juveniles, more    
                                            detached workers      for adults, in         
                                                                  target than control    

Spergel 1995          3                     Conflict mediation,   50% less serious       
                                            job and school        violence for target    
                                            referrals, police     gangs                  
                                            and social workers                           

Goldstein, Glick and  ?                     Anger Replacement     Reductions in gang     
Carthan (1994)                              training for gang     arrests                

Most other evaluated gang programs had far less success than the CYA or Ladino Hills projects, even with the symptoms of community structure. It was not for lack of effort. The intensity of gang worker efforts is described in one summary of the six years of work of the Chicago Youth Development Project (CYDP), a privately-sponsored program combining detached gang workers with community organization (Carney, Mattick and Callaway, 1969: 15, as quoted in Klein, 1995:144):

Staff succeeded in finding 750 jobs for 490 young people; similarly, 950 school dropouts were returned to school 1,400 times. CYDP outreach workers made 1,250 appearances at police stations and courts on behalf of 800 youngster.. Finally CYDP workers made 2,700 follow-up visits to the homes of 2,000 juveniles who were arrested during the last thirty months of the project, in an effort to get them involved in one aspect or another of the project's programs. Despite this effort, the careful evaluation found that the youth unemployment rate remained unchanged, the school dropout rate increased somewhat, and the arrest rates of juveniles in CYDP areas increased over time.

A different and more recent strategy for using gang workers is crisis intervention and conflict mediation. A test of this approach by detached workers in a Puerto Rican area of Chicago had more encouraging, if, complex results (Spergel, 1986, as cited in Spergel, 1995: 255). While the program area had a slower rate of increase in serious gang crimes by juveniles than the comparison area, the program area also had a faster rate of increase in serious crimes by adults. Attempts to organize the target community were less successful than efforts to mediate juvenile gang conflicts to prevent violence. More recently, Spergel has found some evidence that a coordinated police-probation-detached worker program to monitor gang offenders on community supervision has slowed their rate of committing serious violence (Spergel and Grossman, 1995, as cited in Howell, forthcoming). Encouraging results from another conflict-oriented program have been reported for New York (Goldstein, Glick and Carthan, 1994, as cited in Howell, forthcoming). Using a cognitive skills approach called "Anger Replacement Training," the evaluators report decreases in arrests of gang members.

Perhaps the most encouraging findings about gangs come from Boston, where they have nothing to do with traditional gang prevention. Preliminary results of a gang-related project to reduce juvenile firearms crime are extremely encouraging (Kennedy, Piehl and Braga, 1996). An effort to deter gang-related gun violence by massive police response to any shootings is supported by probation officers who have the statutory authority to search probationers at will. The probation officers work with police to send out the word that any shootings will get anyone even tangentially involved into a lot of trouble. This approach has apparently given some gang members a convenient excuse to opt out of planned conflicts, much as the police crackdown on drunk driving in Australia has given barroom drinkers an excuse to refuse extra drinks (Homel, 1994). If the final results of this project confirm preliminary findings, it will be another example of substantially reduced gun crime without any structural changes in community conditions.

The Future of Gang Violence Prevention

While the results of available evaluations are generally negative, the number of careful field tests remains quite small. The average level of scientific rigor in the available evaluations is quite low. Taken together, the studies show weak evidence of no effect. None of the programs address the underlying community risk factors associated with the recent explosive growth in gang activity. Yet new models of gang violence prevention now under development at Harvard and the University of Chicago might well succeed in reducing gang violence without solving the structural problems of the inner-city. Combinations of police, probation officers and civilians who keep gangs under close surveillance may be successful at heading off planned conflicts leading to gun violence. Unplanned encounters of rival gangs leading to shootouts may be harder to prevent, but reduced gun carrying could accomplish that as well. Police-civilian teams checking known and convicted gang members for guns, with appropriate legal authority, could in theory reduce gun carrying and spontaneous shootings.

The enormous concentration of serious violence among gang members suggests the value of further research and development efforts to find effective prevention methods for gang violence. But the state of the scientific evidence suggests the risks of funding gang programs without careful evaluations, whether through block grants or discretionary programs. University of Southern California gang violence scholar Malcolm Klein (1995: 138) states the case clearly:

Consider California, more affected by street gangs than any other state is, by far...the state has 196 cities with street gangs, 60 in Los Angeles County alone. The state's Office of Criminal Justice Planning in fiscal year 1990-91 poured almost $6 million into sixty projects under its Gang Violence Suppression Program. Included were school programs, street work programs, community mobilization, diversion alternatives, and a wide variety of criminal justice enforcement projects. Yet not a dollar went to an independent evaluation of the effectiveness of these projects. Sixty wasted opportunities to assess our efforts seems to be an inexcusable exercise in public irresponsibility.

The fact that Klein's own work demonstrated that a gang "prevention" program actually increased crime rather than reducing it lends special force to his conclusion. The theoretical implications of Klein's work on gang cohesion suggest that much of what police are doing--often supported by federal funds--to suppress gang violence may also be increasing rather than preventing that violence. The seriousness of gang violence provides even more reason, not less, for a high standard of scientific rigor in evaluating gang prevention. What evidence we have clearly shows that good intentions are not enough.

Both old and new strategies could be subjected to more rigorous evaluations. Despite the strength of Klein's findings, for example, they are based on quasi-experimental pre-post designs generally lacking control groups. A large scale test of gang worker strategies across a sample of 100 gangs, with 50 gangs randomly assigned to intervention, might well produce different results. The Ladino Hills project Klein (1995:146) reports is actually quite encouraging; the program was a clear success at diverting gang members from gangs as long as the gang workers stayed on the job. Klein's emphasis on the project's failure to end gang activity in the area for up to two years after the gang workers were withdrawn seems to set an unrealistically high standard. Just because a maintenance therapy did not rise to the level of a permanent vaccine does not make it worthless. Rather, the evidence suggests that Klein has found a way to reduce gang membership. This is a promising finding that merits replication with a more rigorous research design.

New strategies for gang prevention should also be tested at much higher levels of scientific rigor. OJJDP is currently supporting the development and testing of comprehensive community gang prevention efforts, coordinating multiple local agencies and attempting to mobilize community involvement. NIJ is currently supporting firearms crime reduction efforts. Neither approach is currently undergoing a randomized controlled test (level 5) using communities, or gangs, as the unit of analysis. Indeed, it may well be premature to be doing so at this stage until the strategies are sufficiently well-developed. But a clear plan to develop a strategy that can be subjected to more rigorous testing could help move the nation more quickly to discovering effective methods for reducing gang violence.

One objection to this approach is that every city has a unique gang situation, and must design its own program (Klein, 1995: 154). The response to that objection is that most cities lack sufficient data to conduct rigorous evaluations: enough neighborhoods, enough gangs, enough gang violence to control for all the chance factors that can affect results. Limiting evaluations to one gang program or one city at a time would do little to increase available evidence about how to prevent gang crime. It is only by seeking out the commonalities of successful gang prevention programs across areas and types of gangs that the scientific basis for effective prevention can be advanced.


Community-based mentoring programs take a much broader focus on risk factors than gang prevention programs. Both the empirical evidence and theoretical linkages to community risk factors gives solid reason to support much more research and development on this strategy. While it does not have the gang programs' efficiency of focusing on the limited number of juveniles committing the most serious violence, mentoring offers the promise of effectiveness across a much broader population. Some members of that population could well become gang members or serious violent criminals. Mentoring could be a way to prevent that.

Theoretical Rationale for Mentoring

Why should mentoring of a larger at-risk population of pre- and early adolescents be any more effective than detached social workers focused on gangs? Gang social workers, after all, are in effect mentors to gang members. But the general failure of detached workers may be due to their focus on older youths who are already active offenders. Many developmental theorists argue that ages 10 to 14 provide a more promising focus for intervention and prevention (Carnegie Council on Adolescent Development, 1995). The power of peer groups may not be as great in that age-range, and an intensive relationship with a conventional adult could be a powerful influence for youths on the cusp of delinquency.

A more powerful reason for the failure of detached workers with gangs may be insufficient dosage. Given their workloads, they may not have been able to spend enough time with their individual clients, irrespective of age, in order to become a strong role model. A more intense relationship, with "quantity time" of "quality time," between a "mainstream" male adult and a preadolescent or early adolescent boy may directly address several community risk factors for crime:

o fatherless boys; 17 million children now in single parent homes, 25% of all youth and 50% of minority youth (Tierney, et al, 1995: 49)

o lack of legitimate role models

o insufficient "intergenerational closure" with adult influences counteracting peers (Wilson, 1996: 62)

Mentoring provides the highest dosage of adult-child interaction of any formal community-based program. Compared to street workers and recreation program supervisors, mentors can develop much stronger bonds with juveniles at risk. In theory, they can gain the power of "legitimacy" (Tyler, 1990) based on a pattern of respect and support the mentor establishes with the juvenile, so that the mentor's approval and attention becomes a valued resource. That resource then gives the juvenile a "stake in conformity" (Toby, 1957), something to lose if the juvenile gets into trouble with the law.

Mentoring programs described in available evaluations feature three to four meetings a month or more between mentor and child, with each meeting lasting at least for several hours. Community-based mentors see juveniles in a wide range of settings, including home, movies, professional sports, plays and concerts. They may talk frequently on the telephone, with mentees calling mentors as well as vice versa. In contrast to school-based mentoring programs (reviewed in Chapter 5) which generally operate with a heavier emphasis on academic issues and truancy, community-based mentors tend to be involved in more domains of the child's life. They may also provide more resources in the form of entertainment outings. Mentors may be paid or unpaid, college students or adults. All of them receive some sort of training, although the infrastructure supporting mentoring relationships varies. Adult volunteers in the oldest formal mentoring program, the 90-plus year-old Big Brothers and Big Sisters of America (BB/BSA), for example, are subjected to extensive background examination to screen out potential child molesters.

Results of Community Mentoring Evaluations

Careful examination of community-based mentoring evaluations supports a conclusion that they are a promising approach to preventing crime risk factors, notably drug use. While most of the evaluations show no effect, the most rigorous modern evaluation shows a strong effect at reducing drug use, and clear effects at reducing alcohol use and "hitting" among at-risk children. The short-term measurement of those beneficial effects, however, must stand in the shadow of much less encouraging results from a thirty-year followup of an equally rigorous Depression-era mentoring test, the privately-funded Cambridge-Somerville experiment.

Controlled Experiments. The first controlled test of mentoring began in 1937, when recent college graduates were hired and trained to provide an average of two visits a month to the experimental half of a sample of 650 at-risk boys under age 12 at the program's outset.3 The paid social worker mentors met with their clients at home, in the street, or at project headquarters. They provided academic tutoring, trips to concerts and sports events, and general emotional support for the boys. The program also provided the boys' families with help for medical and employment problems, and sent the treatment group boys to summer camp. By 1942, 253 of the original 325 treatment group boys were still in the program, when it was ended so the counselors could join the armed forces.

The results of this intensive mentoring showed no difference between treatment and control groups in criminal records, either in 1942 (Powers and Witmer, 1972) or in 1975-76 (McCord, 1978). The longterm followup, however, did show significantly higher levels of diagnosed alcoholism, serious mental illness, and stress-related physical health problems. A higher level of unfavorable life outcomes, although not specifically greater crime, among the treatment group seems clear. What is less clear is the meaning of the results for the value of mentoring programs today.

Three theories compete to explain these results. One is that mentoring simply backfires, somehow creating an artificial source of support that makes it harder for mentored boys to adjust as adults. A more plausible theory is that the abrupt departure of these long-term counselors from the boys' lives was as damaging emotionally to the boys as a divorce or other loss of parental involvement, compounded in many cases by the boys' previous loss of their own natural fathers' support. A third theory is that the difference in diagnosed mental health problems is only an artifact of the treatment group's greater exposure to professional and medical services as part of the treatment content. Under this theory, the treatment boys had no greater rate of personal problems, but when they had problems they were simply more likely to seek professional help of the kind the program had taught them to seek.

The fundamental principle of science here is that one experiment alone, no matter how rigorous, cannot provide a "definitive" test of any hypothesis. Social experiments in particular require replication to determine their generalizability to other times and places. A three-decade followup is an excellent basis for drawing conclusions about the lifetime effects of a treatment, but it has a substantial drawback for policy analysis: by the time the results are in, the world has changed so much that the results may no longer be valid. The modern social conditions of inner-city poverty and segregation are so different from the context of the Cambridge-Somerville experiment that it is not clear that the identical program would produce similar results.

If three decades are too long, one year is probably too short. Unfortunately, that is all we have in our modern controlled experiment in community-based mentoring for pre- and early adolescents (Tierney and Grossman with Resch, 1995). The virtues of this experiment, however, are many, including the substantial risk factors in the sample. The 959 eligible applicants for the Big Brothers/Big Sisters program in eight cities came from homes in which 40% of the parents were divorced or separated, 15% had suffered a death of a parent, 40% had a family history of substance abuse, and 28% had a history of domestic violence. The children themselves, of whom 60% were minorities, 40% girls, and all aged 10-14, included 27% who had been abused as children. As Chapter Four reports, child abuse substantially increases the risk of criminality in later life.

How much the Big Brothers/Big Sisters program reduces criminality later in life is not clear. What is clear from this tightly randomized experiment is that there were substantial benefits in one year (average) treatment. After spending around 12 hours monthly with their volunteer adult mentors, the treatment group children had 45% less reported onset of drug abuse than the control group children, who had been put on the waiting list.4 They also had 27% less onset of alcohol use, and 32% less frequency of hitting someone. The program also reduced truancy: treatment group children skipped 52% fewer days of school and 37% fewer classes on days they were in school.

These results were achieved at a very modest cost. Since the mentors volunteer their time, the only cost is the infrastructure needed to recruit, screen, train and properly "match" the mentors to children for successful long-term relationships. The cost is estimated at about $1,000 per match (Tierney and Grossman, with Resch, 1995: 52). While the full crime prevention benefits of that cost cannot be specified without a longer-term followup study, the short-term benefits alone might justify federal support of this apparently underfunded program. At a price of $1,000 per year of drug abuse prevented, the taxpayer would be well ahead spending money on this program instead.

Table 3-2

Community-Based Mentoring Evaluations

Primary Source        Scientific Methods    Program Content       Program Effects        
(secondary)           Score                                                              

McCord 1978, 1992     5                     2 visits monthly by   No effect on criminal  
Powers and Witmer                           paid male counselors  record; treatment      
1972                                        for 5.5 years with    group did worse on     
                                            253 At-risk Boys      diagnosed mental       
                                            under 12 in 1937-42;  health                 
                                            WW2 end                                      

Tierney et al 1995    5                     Big Brothers &        46% reduction in drug  
                                            Sisters, 1 year for   use onset, 32%         
                                            10-14 yr.-olds, 60%   reduction in hitting   
                                            minority & 27%        people, relative to    
                                            abused; 3 hrs wkly    controls               

Green 1980            4                     Big Brothers for      No effects on          
(Howell 1995)                               fatherless white      disruptive class       
                                            boys                  behavior; no measures  
                                            1/2 day weekly for 6  of drug use            

Goodman 1972          2                     College Student       high control group     
(Howell 1995)                               Mentors of 10-11      attrition; program     
                                            yr-old boys 6 hrs     effects on crime       
                                            wkly over 2 years     unknown                

Dicken, Bryson and    3                     College Student       no difference in       
Kass 1977                                   mentors for 6-13      teacher-rated          
(Howell 1995)                               yr.-olds, 6 hrs       behavior of mentees    
                                            wkly, 4 months                               

Fo and O'Donnell      5                     12 weeks of paid      Truancy reduced        
1974                                        community mentors     significantly under    
(Howell 1995)                               with at-risk 11 to    some conditions        
                                            17 year olds; N = 26                         

Fo and O'Donnell      5                     1 year of paid        Lower recidivism for   
1975                                        community mentors     treatment groups with  
(Howell 1995)                               meeting weekly with   priors, higher         
                                            at-risk 10-17         without                

Two other randomized experiments in paid "Buddy System" mentoring conducted in Hawaii were published in the early 1970s. The ages of the at-risk youth ranged from 11 to 17, while the ages of the paid mentors ranged from 17 to 65. The first experiment (Fo and O'Donnel, 1974, as cited in Howell, 1995: 91) lasted only 12 weeks, during which it randomly assigned 26 subjects into four treatment groups ( an average of 6 per group). This small experiment used an elaborate theoretical model, in which treatment groups varied on several dimensions. The dimensions included the conditions of mentor approval for the mentees, dichotomized as contingent, or not, on appropriate behavior by the mentees. A third treatment group was paid $10 a month on the same contingent basis. The results showed that truancy declined for the subjects receiving contingent approval, but not for those receiving unconditional approval.

A larger experiment by the same authors abandoned the theoretical distinctions, comparing crime rates between randomly assigned 10-17 year olds receiving mentoring or not (Fo and O'Donnell, 1975, as cited in Howell, 1995: 92). The one-year experiment found that treatment backfired among those with no prior record; those in the experimental group had more offenses during treatment than control group youths who also had no prior record in the baseline period. Among youth who had prior records at the outset of the experiment, however, the results were the opposite: mentees had less recidivism than the control group. The possible reasons for this difference were not reported.

Non-Randomized Evaluations. The other community-based mentoring studies offer little scientific evidence for policy purposes. The Green (1980, as cited in Howell, 1995: 92) evaluation of a Big Brothers' program in Nassau County, for example, lacks any outcome measure of drug abuse, violence or crime. Green does find no difference in disruptive classroom behavior, but so did the Tierney and Grossman with Resch (1995) experiment. The non-randomized design and 6 month followup period also limit its value.

None of the remaining tests are strong enough to contradict the positive effects found in the recent test of Big Brothers/Big Sisters. The Goodman (1972, as cited in Howell, 1995: 90) two-year test of paid mentors in Berkeley (CA) showed some evidence of worse school behavior among mentored at-risk boys than among the controls. Substantial attrition in the control group only, however, made the comparison difficult to interpret. A nonrandom test of a similar approach using unpaid college students for a semester found no differences in teacher ratings of behavior (Dicken, Bryson and Kass, 1977, as cited in Howell, 1995: 91). All of these negative results from what were essentially "start-up" programs may be due to factors that are not present in the standardized, long-practiced methods of the national Big Brothers/Big Sisters program.

The Future of Community-Based Mentoring

The major question about mentoring remains the meaning of the Cambridge-Somerville experiment for contemporary public policy. The answer to that question is unlikely to come from further analysis of that experiment, but from its replication under modern conditions. The Big Brothers/Big Sisters experiment (Tierney and Grossman with Resch, 1995) is an excellent start in that direction, and would be even more valuable if followed by many years of followup data collection. Its promising results, however, suggest the value of a larger test, one that incorporates the diagnosis of community risk factors, as suggested in the conclusions of this chapter.

Based solely on the research available at present, there seems to be sufficient basis to reach somewhat different conclusions than those reached by one OJP publication prepared prior to the publication of the Tierney and Grossman with Resch (1995) experiment, which substantially alters the weight of the evidence. The OJJDP Guide for Implementing the Comprehensive Strategy for Serious, Violent and Chronic Offenders (Howell, 1995: 128) suggests that "mentoring relationships that are noncontingent and uncritically supportive" are "not effective," but that "mentoring relationships that include behavior management techniques" are "potentially promising." The Big Brothers/Big Sisters program reports no contingency policy for mentor approval of mentees. Its success at reducing drug use onset would thus seem to falsify the "contingent approval" hypothesis. The small sample size (N =26) of the one finding consistent with that hypothesis makes the much larger recent study more compelling evidence (Fo and O'Donnell, 1974).

The most important conclusion from this research restates the conclusion of the gang prevention evaluations. Even with the encouraging findings from the most recent controlled test of community mentoring, there is too little information for adequate policymaking. The priority is for more research, not more unevaluated programs. The danger of doing harm is far too great to promote and fund mentoring on a broad scale without carefully controlled evaluations. No such evaluations, to our knowledge, are presently on the drawing boards. They could readily be included, however, as part of a broader test of a comprehensive interventions package in high-crime areas. While the community context of mentoring experiments under those conditions would be unique, the addition of other programs addressing community risk factors could well enhance the potential for crime prevention will adding to scientific knowledge.


The hypothesis that recreation can prevent crime has become one of the most acrimonious in the history of crime policy. More than any other issue, the debate reflects the inappropriate definition of prevention discussed in Chapter 2. What is most revealing about the debate, however, is the virtual indifference it has displayed to empirical evidence. Rather than arguing on theoretical grounds alone, it would seem more valuable to test the hypothesis scientifically. Chapter Five presents evidence that school-based programs have been tested an found ineffective at preventing crime and delinquency. This section presents more limited evidence on community-based recreation centers, where the evidence is thinner but marginally more promising.

An OJJDP publication (Howell, 1995: 95) provides a clear statement of the recreation hypothesis:

An equally plausible negative hypothesis can be suggested on theoretical grounds. In a neighborhood plagued by inter-gang rivalries and everyday anger (Bernard, 1990), after-school recreation creates opportunities for victims and offenders to intersect in time and space (Cohen and Felson, 1979), creating conflicts and potential for violence. One Philadelphia nightclub shooting in the early 1980s, for example, was generated by a fight that began on a recreation center basketball court. A middle ground hypothesis is that the effects of after-school recreation may vary substantially by neighborhood context and how the recreation center is run.

Results of Recreation Evaluations

The scientific evidence on these hypotheses is currently quite limited. What evidence there is all positive, supporting the proponents of recreation programs. While the scientific rigor of the three available evaluations is modest, it shows fairly strong effects, two on crime and one on drugs. Two are based on Boys' and Girls' Clubs (BGC), and two are in public housing.

Table 3-3

After-School Recreation Programs

Primary Source        Scientific Methods    Program Content       Program Effects        
(Secondary source)    Score                                                              

Jones and Offord      3                     Canadian Public       75% reduction in       
1989                                        Housing Project       juvenile arrests for   
(Howell 1995: 95)                           children 5 to 15      experimental, 67%      
                                            offered intensive     increase for control   
                                            recreation, 3 years   location               

Schinke, Orlandi and  4                     3 groups of 5 public  Recreation centers     
Cole 1992                                   housing projects      with drug prevention   
                                            each, 1 group         had lowest drug use;   
                                            Boys/Girls Club       vandalized housing     
                                            (BGC), 1 BCG plus     units down 25% in      
                                            drug prevention, 1    drug prevention sites  
                                            control no BGC                               

Brown and Dodson      3                     Boys' Club area       Program area           
1959                                        compared to 2         delinquency declined   
(Howell 1995: 95)                           comparison areas, 9   after two years,       
                                            years                 comparison rose        

The test in a Canadian public housing project offers the strongest evidence. Over 32 months, the low-income children ages 5 to 15 were provided an intensive after-school program in sports, music dancing, and scouting. A comparison public housing project had only minimal city services. The majority of age-eligible children in the test site participated in the recreation program. Compared to a baseline period of two years prior to the program, arrests of juveniles in the program site declined 75 percent. In the same time period, arrests of juvenile in the comparison site rose 67%. Sixteen months after the program ended the effect had worn off, providing further evidence of a program effect (Jones and Offord 1989, as cited in Howell, 1995:95).

The American public housing test covered three groups of five housing projects each. One group already had a traditional BGC program operating in the community center. A second group received newly established BGC programs, supplemented by the SMART Moves (Self-Management and Resistance Training) substance abuse prevention program aimed at parents as well as children. A third group of three projects had no BGC and remained that way as a control group. Observational and police data indicated a decline in drug use in the new BGC/SMART Moves sites. Archival records showed that vandalized housing units dropped from 8% to 6% of total units in the new BGC sites, while rising from 8% to 9% in the controls and remaining unchanged in the existing BGC sites (Schinke, Orlandi and Cole, 1989).

A nine-year, 1950s study examined juvenile delinquency in a Louisville Kentucky area served by a Boys' Club (Brown and Dodson, 1959). The club included both traditional activities at the building and a summer camp program. The study found declining juvenile delinquency relative to two comparison areas without a Club. The first two years after the Club began operation, however, showed similar trends in delinquency in the program and comparison areas. While the prevention effect could plausibly have taken several years to become evidence, the lack of significance tests and other checks on validity limit the value of this study.

The Past and Future of Recreation Programs

Recreation programs merit further research and development for their potential crime prevention benefits, if only because they continue to draw Congressional support (e.g., Washington POST, January 16, 1997, p. A4). This conclusion is based not just on the three available impact evaluations, but on the long history of such programs in mainstream American life. The widespread availability of such programs in low-crime areas is another structural difference between suburban and inner-city communities, one that may contribute to the latter's higher crime rates.

The danger of violent conflicts being generated by club activities is just as open a question as the potential benefits of the programs. Careful research is needed to assess the net frequency of such conflicts with and without recreation, since shootouts can start off the basketball courts as well as on them. The potential prevention benefits from such programs may well exceed the benefits of prison, perhaps at much lower cost. But we will never know unless we invest in careful evaluation research. More funding of operations alone will leave the policy decision vulnerable to ideological and symbolic politics, rather than a rational decision on the merits of reliable evidence.


Perhaps the most immediate proximate contributing cause to many criminal events is a "criminogenic substance" (Cook and Moore, 1995). Guns, drugs, alcohol and cash, in the right circumstances, can all provide the additional, if not sufficient, cause which helps make a crime happen. That does not mean, however, that these substances will always be in the right circumstances, even when they are available in the community. Guns, for example, may not do much harm if they are kept locked in a safe, even though the potential for theft of the guns may make them a potential cause of a shooting on the street. Similarly, the context and use of alcohol varies widely, and is only criminogenic in some settings.

One approach to community crime prevention is to limit access to criminogenic substances. Community groups often lobby against the renewal of tavern liquor licenses, for example, on the grounds that the alcohol access increases the rates of robbery and assault in the community. Many cities are increasingly concerned about 24-hour bank cash-dispensing machines, with increasing regulatory control of their locations and security measures (Sherman, 1995). Low-income communities have possibly had fewer robberies and thefts since direct bank deposit of welfare and Social Security checks became common a decade ago.

These ideas are generally theoretically sound, given the prevailing theory of criminal events (Felson, 1994). Few of them have been evaluated. One specific approach that has been evaluated, gun buyback programs, suggests that there can be a major gap between theory and practice.

Gun buyback programs are based on two hypotheses. One is that the more guns in a community, the more gun violence there is. There is substantial evidence to support that claim (Reiss and Roth, 1993). The second hypothesis, however, is not supported by the evidence. That hypothesis is that offering cash for guns in a city will reduce the number of incidents in which guns are used in crime in that city. Four evaluations reviewed in Figure 4 show no effects of gun buyback programs on guns. There are several reasons why buyback programs may fail to reduce gun violence:

o they often attract guns from areas far from the program city

o they may attract guns that are kept locked up at home, rather than being carried on the street

o potential gun offenders may use the cash from the buyback program to buy a new and potentially more lethal firearm; the buyback cash value for their old gun may exceed market value substantially.

The enormous expense of these programs is instructive. When St. Louis invested $250,000 in gun buybacks in 1994, the same funds could have been used to match 250 children with Big Brothers/Big Sisters. Those 250 children would then have enjoyed about half the risk of becoming drug users, at least for the first year (Tierney and Grossman with Resch, 1995). But the opportunity cost of the programs never entered into the debate.

The scientific rigor of the buyback evaluations is not great. They can be summarized as providing moderate evidence of no effect. They fail to show effects on gun crimes relative to a comparison of trends in the same types of crimes committed without guns. Given their high cost and weak theoretical rationale, however, there seems little reason to invest in further testing of the idea.

Table 3-4

Gun Buyback Evaluations

Source                Scientific Rigor      Program Content       Program Effects        

Rosenfeld 1995        3                     1991 Gun Buyback in   No reduction in        
                                            St. Louis of 7,500    homicides or gun       
                                            guns                  assaults relative to   
                                                                  same offenses, no      

Rosenfeld 1995        3                     1994 Gun Buyback in   No reduction in        
                                            St. Louis of 1200     homicide or gun        
                                             guns                 assaults relative to   
                                                                  same offenses, no      

Callahan et al 1995   3                     1992 Seattle Gun      No effect on crime     
                                            Buyback               reports or medical     
                                                                  records of gun         


This chapter has shown that there is a substantial disconnection between what is known about community causes of serious violence and what this nation is doing about those causes. The scientific evidence that communities matter is strong. The evidence that serious crime is concentrated in a very small number of communities is even stronger. But the link between those facts and the design of prevention programs is very thin indeed. Instead, a National Academy of Sciences report concludes there is evidence that federal and local transportation and housing policies over the past half-century have substantially contributed to the causation of serious crime, especially in the hypersegregated inner cities where over half of all homicides occur.

Despite the past gap between causation and prevention, there are many as-yet unevaluated new efforts on the horizon attempting to bridge that gap. There is also promising evidence that some programs can be successful without addressing the root causes diagnosis of causation. Thus the prospects for progress in community-based prevention may be stronger than the current evaluation record suggests.

By the criteria used in this report, there are no community based programs of "proven effectiveness" by scientific standards to show with reasonable certainty that they "work" in certain kinds of settings. There are programs for which we can conclude the evidence shows with reasonable certainty that they do not work, at least in the settings where they have been evaluated. But even these programs might be found effective if varied in significant ways and rigorously evaluated. Moreover, there is both empirical evidence and theoretical reason to conclude that some programs are promising enough to merit further replication and evaluation.

What's Promising

o Gang violence prevention focused on reducing gang cohesion, but not increasing it

o Volunteer mentoring of 10 to 14 year-olds by Big Brothers/Big Sisters is promising for the reduction of substance abuse, but not delinquency

What's Doesn't Work

o Community mobilization against crime in high-crime inner-city poverty areas

o Gun buyback programs operated without geographic limitations on gun sources


These findings offer some answers to the Congressional question about the effectiveness of DOJ crime prevention programs. Perhaps most important is the scientific support for the growing emphasis on comprehensive programs for high crime communities found throughout the Office of Justice Programs (OJP). With the advent of the Enterprise Zone/Empowerment Communities (EZ/EC) initiative, the emphasis on comprehensive risk factor strategies is spreading to the entire federal executive branch. The scientific evidence supports this approach, especially to the extent that it actually concentrates on the specific neighborhoods in which serious crime is most heavily concentrated--not just the cities in which those neighborhoods are located. Because this review finds no community-based programs of scientifically proven effectiveness to employ in those high-crime communities, however, there is a critical need for further research and development to help focus that funding more effectively. And because the statutory plan allows states to expend DOJ funds in communities with moderate to low rates of serious youth violence and risk factors for crime and delinquency, the expenditure of the funds is not yet optimal for discovering programs of proven effectiveness in those areas.

Several DOJ funding programs provide support for community-based local prevention programs. The major funding areas are Byrne Grants, Weed and Seed, Local Law Enforcement Block Grants, and the Title V Delinquency Prevention Grants. Most important, however, may be the DOJ funding for rigorous program evaluations of community-based prevention.

Byrne Grants

The Byrne Formula Grant program (as distinct from discretionary grants--see Chapter One) awarded $1.8 billion through the states and territories from 1989 through 1994 (Dunworth, et al, 1997: 5). Community crime prevention, property crime prevention, and public housing are three of the twenty-one original (now 26) "Purpose Areas" for the program. Grants funded under these purpose areas could generally fall in the institutional setting addressed by this chapter. Together the three purpose areas received approximately $68 million, or less than four percent of the total funding. Drug treatment is a fourth Purpose Area operating at the community level, receiving $107 million in those years or 6 percent of total formula grants.

As noted in Chapter One, the broad diversity of programs funded and general absence of scientifically rigorous impact evaluations makes it impossible to assess the effectiveness of the Byrne funding stream as a single policy. Even the specific Byrne Purpose Areas cover a broad range of local programs. The scientific evidence reviewed in this chapter, however, strongly supports the statutory language calling for "strategic plans to target resources on geographic and substantive areas of greatest need" (Dunworth, et al, 1997: 3). The key question raised by this chapter is the best criteria for selecting the areas of greatest need. A related question is the most appropriate definition of "area." Absent a clear focus on the geographic areas with the most serious crime, community-based programs offer little scientific basis for claims of effectiveness at preventing such crime.

The evidence suggests that community-based Byrne grants may be most effective if concentrated on the small number of census tracts (often contiguous) where the majority of homicides in each state are clustered. The scientific evidence on the geographic distribution of homicides shows strong concentrations within high risk-factor census tracts. While a decade ago it would have been difficult for many states to analyze homicide data statewide by census tract, recent advances in microcomputers and computerized crime mapping makes such analysis feasible. Not every high homicide area may be appropriate for Byrne funding, given the difficulties of implementing community-based programs. But a statutory plan to focus a substantial percentage--perhaps fifty percent or more--of community-based Byrne Grant programming within such communities could speed the process of discovering what works. This would be especially likely if coupled with a national plan for testing community-based strategies across large samples of communities (see below).

The issue of concentration helps to interpret the evidence on community mobilization. That evidence shows that, by itself, mobilization is ineffective against serious crime in low-income communities. But it is far to early to close the door on mobilization as a possible necessary condition for other strategies. Many questions remain about whether mobilization can enhance a wide range of other specific efforts to attack serious crime, such as helping police reduce illegal gun carrying, reducing the availability of drugs and alcohol, and divert youth from gangs. Those questions, again, can only be answered by large sample community level studies as recommended below. In the absence of such programming for the sake of discovering what works, however, community mobilization funding would be of doubtful effectiveness.

Concentration of funds on high-crime communities would also make it possible to evaluate programs like drug treatment in a community-based way. Rather than examining the effects of drug treatment on individual-level crime rates, a community-level concentration of drug treatment could measure the community crime prevention effects of substantial increases in local treatment slots. The individual-level evidence we do have on drug treatment (see Kinlock, 1991), however, is certainly supportive of the effectiveness of Byrne funding spent on that Purpose Area.

Local Law Enforcement Block Grants

This formula grant program newly established in 1996 is also more focused on high-crime communities than other federal funding of local crime prevention. Most of the $404 million in 1996 funds were allocated on the basis of each local police agency's level of reported Part I violent crimes. The statutory distribution plan clearly places greater resources in the cities with the most serious problems of violence and youth violence. It does not, however, require that the funding be concentrated within those cities in the areas of greatest risk.

Like the Byrne Program, Local Law Enforcement Block Grants (LLEBG) could be focused more precisely on census tracts with highest homicide rates. And like the Byrne grants, LLEBGs have awarded substantial support for community mobilization. The 1996 amount was $33 million, about nine percent of program funding. The comments above about further funding of community mobilization programs under Byrne apply to LLEBG as well; more investment in discovering what works seems justified, while unevaluated funding is likely to be ineffective at either preventing crime or increasing scientific knowledge about prevention.

Weed and Seed

Since 1991, the Weed and Seed program (see Chapter One) has been the most theoretically appropriate federal funding program for dealing with concentrated inner-city violence. Based upon the available DOJ publications, Weed and Seed funding offers the clearest focus on the census tracts with very high homicide rates; the initial program area in Kansas City had a rate of 180 per 100,000, or twenty times the national average. As the first of many comprehensive inner-city programs developed in recent years by OJP, Weed and Seed also offers the best evidence on the challenges of implementing and evaluating comprehensive programs, especially those in which DOJ becomes the lead agency in mobilizing resources from other federal departments at a micro-local level.

Weed and Seed's rationale for preventing serious crime is a high concentration of resources addressing a high concentration of risk factors in a small geographic area. The basic structure of this approach apparently differs from the majority of DOJ funding, which by statute cannot be focused upon the highest-crime communities. Given enough evaluation evidence for programs of proven effectiveness in such places, there could be a strong rationale for channeling the majority of DOJ crime prevention funding in ways similar to Weed and Seed. The challenge for Weed and Seed is therefore not just to prevent crime in the target communities, but to do so in a way that allows scientific evidence to accumulate about program effectiveness. The initial history of the program in that regard is instructive.

The initial Weed and Seed target area in Kansas City was accompanied by an NIJ evaluation grant that was almost equal to the amount of the program funding. That evaluation found a 49 percent reduction in gun crime and a statistically significant reduction in homicide associated with a single element of the program that fell outside the community-based institutional setting of this chapter (see Chapter Eight): directed police patrols at computer-located "hot spots" of gun crime (Moore, 1980). These patrols produced a 65 percent increase in gun seizures not found in the comparison area, where gun crime remained stable (Shaw, 1994; Sherman, Shaw and Rogan, 1995). The single element could be evaluated because none of the other elements had been implemented at that time. Had there been other elements implemented, it would have been scientifically impossible to isolate the effects of this element. Fortuitously, the delay in the other program elements allowed the evaluation to discover an apparent effect with important implications.

Subsequent Weed and Seed sites did not have such intensive evaluations. The 50-50 ratio of evaluation to program dollars was tipped overwhelmingly in favor of program dollars. In the five years since the subsequent site funding was awarded, no impact evaluation has been completed. A process evaluation published by NIJ (Roehl, et al, 1996) illuminated the complexity of the program, which has now attracted substantial state and private funding in some sites. A second multi-site evaluation is now in progress, which is slated to produce site-specific impact evaluations at a Scientific Methods Score of either 2 or 3. The ability of that retrospective design to isolate program elements in relation to crime prevention will be difficult given the problem of multiple treatments (Cook and Campbell, 1979). Thus as the program currently stands, there is good scientific theory but no scientific data to show the effectiveness of the program.

The most challenging theoretical element for any inner-city crime prevention program is raising the community rate of adult labor force participation (Wilson, 1996). Chapter Six discusses the evidence on that point in detail. Labor force programs have suffered from a lack of focus on the Weed and Seed strategy, scattering resources across individuals spread out over many disparate communities. More recent private and public efforts to change community labor markets, rather than personal labor skills, fit right into Weed and Seed (see Bloom, 1996). They can easily become an integral part of its multi-risk factor reduction strategy, coupling high enforcement with greater opportunity.

Comprehensive Communities Program

Similar in conception to Weed and Seed, the Comprehensive Communities Program (CCP) is an effort to integrate social programs and policing, public and private organizations to control crime and improve the quality of life. The major difference is a lower funding level (see Chapter One) and a less clear-cut focus on addressing the highest-crime, highest risk factor areas. CCP is more flexible about specific priorities set by city-wide leadership for specific programs and areas in which to operate them. The scientific evidence is thus less helpful in assessing such a program, given its greater variability. An intensively measured level 2 process and impact evaluation is currently under way (Rocheleau, et al, 1996), but there is no well-controlled test of its crime prevention effectiveness in progress. To the extent that some sites rely on gang programs that are of uncertain safety and effectiveness, as this chapter has shown, controlled tests of those specific program elements would be a high priority.

Title V Community Prevention Grants Program

Since 1992, this program has assisted local juvenile justice agencies to collaborate with other youth-serving agencies to develop an integrated system of services designed to prevent delinquency (see Chapter One). A major prevention component of this strategy is based on the Communities That Care model (CTC; Hawkins, Catalano, & associates, 1992). Consistent with the scientific evidence of concentrated risk factors, but not with the micro-local focus discussed in this chapter, the CTC model recommends a flexible plan for reducing risk factors. The plan is for local jurisdictions to identify risk factors known to be associated with delinquent behavior, to identify protective factors that buffer the effects of the identified risk factors operating within the communities, and to target program interventions on those factors. Like Weed and Seed, this program has a firm foundation in indirect empirical evidence and theoretical support. What it lacks to date is scientifically rigorous crime prevention impact evaluations.

The Title V program is implemented in two phases. During phase one, the assessment and planning phase, communities (defined here as entire jurisdictions, not neighborhoods) interested in participating in the Title V program must form a local prevention policy board and conduct an assessment to identify and prioritize the risk factors operating in their community. On the basis of this assessment, the applicant community then must develop a specific, comprehensive 3-year delinquency prevention plan. This plan serves as the basis for the community's application to the state's juvenile justice advisory group for Title V funding. Phase two of the process involves the implementation, monitoring, and evaluation of the programs and services. A 1996 survey administered by GAO showed that most of the 277 local projects supported by this program appeared to be designed in accord with the CTC model.5 For example, 78% reported addressing multiple risk factors in three or more substantive problem areas, and about 90% reported that they used two or more strategies identified in the CTC materials as "promising." Common prevention activities include parent training in effective techniques of conflict resolution and after-school programs.

The CTC model recommends local monitoring of changes in risk and protective factors at the community (city or county) level, but that will yield limited insights on crime prevention effectiveness. A national evaluation of Title V is being planned, but its scientific strength will be limited in the absence of random assignment of funding, or at least of different prevention strategies, to some communities and not others (Farrington, 1997). The scientific possibilities for comparing two different approaches consistently applied within two equivalent groups of communities, especially at the neighborhood level, would appear to be quite strong (Boruch, 1996). But whether it will happen depends in large part on the future of the issues and recommendations presented in Chapter 10.

Based on our review of the evaluations of the programs in the OJJDP "menu" for Title V (Howell, 1995) in Chapters 2,3,4,7 and 8, we can make a limited assessment of the potential effectiveness of this crime prevention program. The framework provided for the Title V incentive grants focuses local jurisdictions on selecting prevention strategies that have some basis in research. It is possible, however, that the array of "promising" activities allowed under the model is too broad, encompassing some ineffective strategies along with the more effective ones. The GAO report describes activities undertaken with Title V funds in six jurisdictions. These descriptions are too general to support a judgement of the delinquency prevention potential of any particular activity, but they seem to encompass a wide range of activities. Some of these, such as social skills training (see Chapter Five) mentoring programs, appear promising. Others, such as peer mediation and sports programs, do not.

Gang Prevention and Intervention

Funding for gang prevention and intervention programs is provided by BJA's Byrne formula grants, OJJDP, and potentially by Weed and Seed and Local Law Enforcement Block Grants. There are currently no restrictions on the kinds of gang programs that are eligible for support. The scientific literature suggests, but at a moderately low level of certainty, that the approach taken to gangs is critically important. It is possible that DOJ funding is supporting programs that reduce gang cohesion, in which case they are more likely to be effective. It is also possible that DOJ funds support programs that work with gangs in ways that may increase their cohesion, in which case they are less likely to be effective. Since the results of the available evidence cannot yet be generalized at a very high level of certainty, it is fairer to say that absent further evaluation evidence, the effects of DOJ-funded anti-gang programs are unknown.

JUMP:Juvenile Mentoring Program

This national discretionary program is a line-item Congressionally earmarked appropriation for both schools and nonprofit organizations to establish mentoring programs for juveniles (See Chapter One). The school-based mentoring evidence discussed in Chapter 5 is less encouraging than the findings from the Big Brothers and Sisters experiment reviewed in this chapter, but the school-based studies were also less rigorous. The $4 million annual appropriation since 1994 was increased to $15 million in FY 1997. No impact evaluations of JUMP have been completed, but one was solicited in 1996.6 Based on the available scientific evidence, the drug abuse prevention effectiveness of the Big Brothers/Big Sisters model is promising, but the school based model is of unknown effectiveness.

Based on the 1996 evaluation solicitation, it seems unlikely that the effectiveness of JUMP will be measured scientifically in the near future. JUMP is yet another rapidly developing program that would benefit more from Congressional appropriations for evaluation than for expanded operations. The 1996 evaluation was budgeted at $150,000 per year to assess the effectiveness of a $4 million annual appropriation covering 41 separate grantees, or about $3600 of evaluation funding per program grantee. While JUMP is ideal for the kind of level 5 evaluation conducted in the private sector using randomized controls (Tierney and Grossman, with Resch, 1995), the under-funded DOJ evaluation clearly made controlled testing by independent evaluators impossible. The design's reliance on program grantees for data collection compromises the independence and reliability of the data, and probably precludes such methods as obtaining police records on juvenile arrests as an outcome measure. The Congress could correct these limitations by providing twenty percent of program funds for a more limited number of JUMP sites to be evaluated using the same design as the Tierney et al (1995) study.

STOP Formula Grants to Combat Violence Against Women

This program requires that states spend 25% of their funds to prevent violence against women on each of three priority areas (see Chapter One): law enforcement, prosecution, and victim services. None of these fall into community-based crime prevention, but grants under the remaining 25 percent may well do so. The purpose of the money is not just to combat domestic violence (see Chapter Four), but also to prevent stranger violence against women in the community. Hence community-based programs to reduce rape, stalking, purse-snatchings and carjackings would also be relevant here. The initial NIJ process evaluation of the program did not identify any community-based programs (Burt, 1996), nor was our review able to identify any impact evaluations of community prevention programs for stranger violence against women.


Community-based programs are among the most difficult to evaluate. They may also be the most important. The "small science" approach to evaluations of community programs has prevented the discovery of programs of proven effectiveness in this vital institutional setting. The effectiveness of community prevention might be greatly increased by a substantial investment in more controlled testing of program effects on serious crime. The Department of Labor has invested $15 million in a randomized test of a single job training program. The prevention of serious crime in communities where it is heavily concentrated should warrant at least that much.

A fast-track strategy for advancing knowledge about community crime prevention is a multi-level randomized trial, with experiments imbedded in experiments. Mentoring programs, for example, can be randomly assigned to half the communities. Then within communities, the program can be provided to half the applicants. Gang prevention strategies for reducing cohesion can be randomly assigned to half of the communities, and then within half of the communities receiving the program it can be randomly assigned to half of the gangs. If "communities" are defined at the level of Census tract, there could be several hundred units of analysis available for this kind of multi-level research design.

The design could also embody elements that would always be delivered to the entire community. Substantial increases in police patrol, for example, could greatly reduce the crime rate in the short run. That, in turn, could assist efforts to attract new employers to the community, creating long-term employment opportunities. That, in turn, could diversify the class and race composition of the neighborhood, reducing hypersegregation on both variables as a risk factor. Drug prevention programs, recreation centers, school and family-based programs could be added as well. While many of these elements are already part of OJP funding plans, the method of testing them in randomly assigned combinations is not.

A broader experiment in community-based mentoring could draw separate samples from systematically different communities, chosen on theoretical grounds. A contemporaneous trial in two segregated inner-city communities of concentrated poverty, two predominantly white but high single-parent family suburban areas, and two racially and economically mixed areas would answer a key question: is whether the effects of the mentoring program vary by community context. An added comparison of Hispanic and African-American poverty areas would also illuminate the role of ethnicity, if any, in conditioning the effects of community-based mentoring. Separate random assignment schedules in each location would allow a strong test of interaction effects, rather than the multivariate correlational methods used in the Tierney and Grossman with Resch (1995) test.

The importance of testing mentoring in different communities is clear. Many prevention strategies evaluated in this report produce different effects for different kinds of people, and in different community contexts. The Cambridge-Somerville experiment is a caution that mentoring, like gang intervention, may well backfire. It would be a mistake of both science and policy to support community-based mentoring for all communities on a one-size-fits-all basis. While that may well be the ultimate result of such a research program, the possibility of differential effects must be carefully examined.

Additional elements for a national experiment for dealing with high crime communities are suggested in the following chapters. Regardless of the specific elements included, the scientific basis for such an experiment remains the same. While scientists clearly disagree over the best way to handle the difficulties of community-level prevention (Bloom, 1996; Farrington, 1997), there is substantial agreement that we are not learning enough about the relative effectiveness of different strategies for community-based crime prevention.


1Sampson and Lauritsen, 1993: 89.

2While community crime rates have clear correlations with risk factors, there is still no scientifically conclusive evidence of causation, for reasons summarized in Sampson and Lauritsen (1993) at pp. 75-83. Thus the term "cause" in this section is used flexibly to denote a high priority target for a public policy intervention, a risk factor whose elimination might reduce crime.

3Whether this program is properly characterized as a mentoring program or something else is an issue debated within the University of Maryland team, one that illustrates the difficulty of characterizing multi-dimensional programs on the basis of any one dimension.

4Control groups and randomized experiments are generally far more possible ethically than many public officials are willing to concede, giving the scarcity of resources. Waiting lists are an excellent opportunity for controlled experiments. In this case, the control group males waited no longer than the applicants on the waiting list.

5This section is based largely on a recent (August, 1996) G.A.O. report entitled “Status of Delinquency Prevention Program and Description of Local Projects.”

6Office of Juvenile Justice and Delinquency Prevention, FY 1996 Discretionary Competitive Program Announcements and Application Kit, p. 25.


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