The FBI's National Incident-Based Reporting System (NIBRS) collects information on each crime reported to law enforcement agencies, including the date and time that the crime was committed. Analyses of these data document that the most likely time for committing a violent crime is different for juveniles and adults.

A new analysis of NIBRS data using the FBI's master files from 1991 through 1996 confirms earlier findings. In general, the number of violent crimes committed by adults increases hourly from 6 a.m. through the afternoon and evening hours, peaks at 11 p.m., and then drops hourly to a low point at 6 a.m. In stark contrast, violent crimes by juveniles peak in the afternoon between 3 p.m. and 4 p.m., the hour at the end of the school day.

While adult robberies and aggravated assaults present similar temporal patterns, the juvenile patterns differ   Aggravated assaults by juveniles are most common around 3 p.m., while the number of juvenile robberies peaks around 9 p.m. About two-thirds of all serious violent crimes are aggravated assaults, so they control the overall temporal pattern of serious violent crime. Note: Serious violent crimes include murder, violent sexual assault, robbery, and aggravated assault. Data are from 12 States (Alabama, Colorado, Idaho, Illinois, Iowa, Massachusetts, Michigan, North Dakota, South Carolina, Utah, Vermont, and Virginia). Source: Authors' analyses of the FBI's National Incident-Based Reporting System master files for the years 1991-1996 [machine-readable data files].

The importance of this afterschool period in understanding the patterns of juvenile violence is confirmed when the days of the year are divided into two groups: school days (i.e., Monday through Friday, excluding holidays, in September through May) and nonschool days (all days in June through August, all weekends, and holidays). A comparison of the crime patterns for school and nonschool days finds that the 3 p.m. peak occurs only on school days. The time pattern of juvenile violent crimes on nonschool days is similar to that of adults, with a gradual increase during the afternoon and evening hours, a peak between 8 p.m. and 10 p.m., and a decline thereafter. Therefore, on both school and nonschool days, the level of juvenile violence is relatively low during the time period when juvenile curfew laws are in effect.

Afterschool programs have more crime reduction potential than juvenile curfews

The number of school days in a year is essentially equal to the number of nonschool days in a year. Based on NIBRS data, 57% of all violent crimes by juveniles (i.e., murder, forcible rape, robbery, and aggravated and simple assault) occur on school days. In fact, 19% of all juvenile violent crimes occur in the 4 hours between 3 p.m. and 7 p.m. on school days. A similar proportion of juvenile violent crime (21%) occurs during the standard juvenile curfew hours of 10 p.m. to 6 a.m. However, the annual number of hours in the curfew period (i.e., 8 hours every day) is four times greater than the number of hours in the 3 p.m. to 7 p.m. period on school days (i.e., 4 hours on one-half of the days in the year). Therefore, the rate of juvenile violence in the afterschool period is four times the rate in the juvenile curfew period. This analysis suggests that the potential for reducing a community's juvenile violent crime rate is greater for efforts to reduce juvenile crime after school than for juvenile curfews.

Serious juvenile crimes cluster in the hours immediately after the close of school   On school days, robberies and aggravated assaults by juveniles both peak at 3 p.m.; unlike aggravated assaults, robberies also peak at night. The temporal pattern of juvenile violence on nonschool days is similar to the overall pattern for adults; juvenile violence peaks at night on nonschool days. Note: Serious violent crimes include murder, violent sexual assault, robbery, and aggravated assault. Data are from 12 States (Alabama, Colorado, Idaho, Illinois, Iowa, Massachusetts, Michigan, North Dakota, South Carolina, Utah, Vermont, and Virginia). Source: Authors' analyses of the FBI's National Incident-Based Reporting System master files for the years 1991-1996 [machine-readable data files].

Sexual assaults by juveniles peak in the hours after school

The most likely hour of a school day for a juvenile to commit a sexual assault is between 3 p.m. and 4 p.m. In fact, more than 1 in 7 sexual assaults by juveniles occur in the 4 hours between 3 p.m. and 7 p.m. on school days. Unlike other violent crimes, sexual assaults by juveniles on nonschool days are most likely to occur between noon and 1 p.m.

Juveniles injure more victims in the hours around the close of school than at any other time   Violent crime with injury The number of persons injured by adult offenders increases through the afternoon and evening hours and peaks around 11 p.m.   In general, the temporal pattern of violent crimes committed by juveniles with firearms is similar to the adult pattern, except for the high proportion of juvenile firearm-involved crimes that occur immediately after school on school days   Violent crime committed with a firearm   Note: Violent crime includes murder, violent sexual assault, robbery, aggravated assault, and simple assault. Data are from 12 States (Alabama, Colorado, Idaho, Illinois, Iowa, Massachusetts, Michigan, North Dakota, South Carolina, Utah, Vermont, and Virginia). Source: Authors' analyses of the FBI's National Incident-Based Reporting System master files for the years 1991-1996 [machine-readable data files].

1999 National Report Series, Juvenile Justice Bulletin: Violence After School	November 1999