RELATIONSHIP BETWEEN THE OFFENDING FREQUENCY (λ) OF IMPRISONED AND FREE OFFENDERS*

In the public debate over incarceration policy, there is considerable disagreement about what value of individual offending frequency (λ) is appropriate to use in estimating incapacitative effects. This article provides an approach for estimating the mean values of λ for diverse subsets of the total offender population, with particular emphasis on subsets generated by filtering through various stages of the criminal justice system. Sharp differences in offending frequency are displayed between robbery and burglary inmates, across three states, and particularly between resident inmates and free, active offenders. Free offenders average 1 to 3 robberies and 2 to 4 burglaries per year, while resident inmates have λ values 10 to 50 times higher. Differences result from the underlying levels of criminal activity and the sanction Levels that offenders face. A highly heterogeneous distribution of offending frequency in the total population of offenders combines with relatively Low imprisonment levels to lead to substantial selectivity of high-λ offenders among resident inmates and a correspondingly low mean value of λ among those offenders who remain free. These results have important implications for estimating incapacitative effects of an increase in incarceration, since the additional inmates will be drawn from free offenders whose mean λ is at least an order of magnitude Lower than that of the current inmate population.     

ESTIMATING INTERVENTION EFFECTS IN VARYING RISK SETTINGS: DO POLICE RAIDS REDUCE ILLEGAL DRUG DEALING AT NUISANCE BARS?*

This paper investigates the effectiveness of police raids in reducing drug dealing in and around nuisance bars. We examine effects of both dosage (number of raids) and duration (months) of the intervention, as well as the conditioning effects of land use and population characteristics in shaping the underlying risk levels of drug dealing in the target and surrounding areas. Results indicate that the police intervention suppresses levels of drug dealing during periods of active enforcement, but the effects largely disappear when the intervention is withdrawn. Also, the effects of the intervention are mediated by risk characteristics in target and surrounding areas. Target areas characterized by higher levels of risk are more resistant to intervention effects than those with lower levels of risk. Risk factors in nearby areas are also significant. Bars with high levels of risk arising from land uses in surrounding areas are easier to treat, while bars with high levels of population‐based risk in surrounding areas are harder to treat.     

TREND AND DEVIATION IN CRIME RATES: A COMPARISON OF UCR AND NCS DATA FOR BURGLARY AND ROBBERY*

Trends and year-to-year deviations in UCR and NCS data on burglary and robbery are examined for the period 1973 to 1985. We find strong correspondence between year-to-year deviations in UCR crime rates and NCS victimization rates for both crime types. The difference between the two data series lies primarily in their contrasting trends, although there is some evidence that trends in UCR and NCS crime rates have been converging in recent years. Ex post forecasts reveal that the UCR/NCS relationships estimated from the 1973–1985 data continued through 1986 and 1987. Although the UCR rates in 1986 were somewhat influenced by unusual increases in the proportion of crimes reported to the police that year, changes in crime reporting for the period as a whole have had little effect on UCR burglary and robbery rates. We conclude that, within the two serious crime types examined in this study, there is strong consistency between the alternative data sources on variations in crime rates over time.     

CRIMINAL CAREER RESEARCH: ITS VALUE FOR CRIMINOLOGY*

In a recent paper published in this journal, Gottfredson and Hirschi (1986)¹ argue that the concepts of criminal careers, career criminals, selective incapacitation, prevalence, and incidence, and longitudinal studies all have little value for criminology. In our view their paper misrepresents these concepts and our research on these topics. We are pleased to have the opportunity in this paper to develop these concepts more clearly and to show their relevance for criminology.