Each data source as its strengths and weaknesses. Although each data source is quite different than the others, all data sources actually agree on the nature of criminal behavior and show stable patterns in the crime rate. Ecological patterns show that some areas of the country are more crime-prone than others, that there are seasons and times for crime, and that these patterns are quite stable. There is also evidence of gender and age gaps in the crime rate, with men usually committing more crime than women and young people committing more crime than the elderly. Crime data show that people commit less crime as they age, but the significance and cause of this pattern are not completely understood. Similarly, racial and class patterns appear in the crime rate. However, it is not clear whether these are true differences or a function of discriminatory law enforcement. One of the most important findings in crime statistics is the existence of the chronic offender, a repeat criminal responsible for a significant amount of all law violations. Chronic offenders begin their careers early in life and, rather than aging out of crime, persist into adulthood. The discovery of the chronic offender has led to the study of developmental criminology--why people persist, desist, terminate, or escalate their deviant behavior. 143 notes, 2 tables, 10 figures, and 6 photographs