How Many Latent Classes of Delinquent/Criminal Careers? Results from Mixed Poisson Regression Analyses (original) (raw)
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Criminology, 1993
This article addresses three issues that are central to the criminal career debate. First, is the life course of individual offendingpatterns marked by distinctive periods of quiescence? Second, at the level of the individual, do offending rates vary systematically with age? In particular, is the agecrime curve single peaked or flat? Third, are chronic offenders different from less active offenders? Do offenders themselves differ in systematic ways? Using a new approach to the analysis of individual criminal careers-based on nested, mixed Poisson models in which the mixing distribution is estimated nonparametrically-we analyze a panel data set that tracks a sample of males for more than 20 years. Our results provide empirical evidence in support of some features of criminal propensity theory and some in support of conventional criminal careers theory. In support of latent-trait criminal propensity theory, the individual-level average offense rate (per unit of time) varies as a function of observable individuallevel characteristics and unobservable heterogeneity among individuals, and the age trajectory of the oflense rate is generally single peaked rather than flat. On the other hand, in support of conventional criminal careers theory, models that incorporate a parameter that permits periods of active as well as inactive offending across age have greater explanatory power than those that do not. In addition, the nonparametric, discrete approximation to the population distribution of unobservable heterogeneity in the individual-level mean offense rate facilitates identification of four classes of offenders-nonoffenders as well as individual-level characteristics that are unique to each group. Problems of theoretical explanation and empirical generalizability of these results are described. With this article we wade into a long-standing and sometimes contentious * The research reported here was supported, in part, by National Science Foundation grant SES-9210437. We thank Jacqueline Cohen, David Greenberg, Douglas Smith, Terrie Moffit, and an anonymous referee for helpful comments.
Criminal Careers of Serious Delinquents in Two Cities
Youth Violence and Juvenile Justice, 2004
Because different methods for studying criminal behavior all suffer from important limitations, it is useful to apply different methodologies to the same population whenever possible. In this analysis, we examine the relationships between self-report and official record-based measures of offending activity using populations of adolescent serious offenders in Phoenix, Arizona, and Philadelphia, Pennsylvania.
Mixtures of Participation and Frequency During Criminal Careers Over the Life Span
2009
Recent advances and debates surrounding general/developmental and static/dynamic theories of crime can be traced to the 1986 National Academy of Science Report on criminal careers and the discussion it generated. A key point of contention lies in the interpretation of the age-crime curve. For Gottfredson and Hirschi, the decline in the agecrime curve in early adulthood reflects decreasing individual offending frequency (λ) after the peak. Blumstein et al. claim that the decline in the aggregate age-crime curve can also be attributable to the termination of criminal careers, and the average value of λ could stay constant (or increase with age) for those offenders who remain active after that peak. Using data from the Criminal Career and Life Course Study including information on criminal convictions over 60 years of almost 5,000 persons convicted in the Netherlands and applying a Two-Part Growth Model that explicitly distinguishes between participation and frequency the paper assesse...
Modelling ‘crime-proneness’. A comparison of models for repeated count outcomes
2010
In the criminal career literature, the individual-level age-crime relationship is commonly modelled using generalized linear mixed models, where between-individual heterogeneity is then handled through specifying random effect(s) with some distribution. It is common to specify either a normal or discrete distribution for the random effects. However, there are also other options, and the choice of specification might have substantial effect on the results. In this article, we compare how various methods perform on Norwegian longitudinal data on registered crimes. We also present an approach that might be new to criminologists: the Poisson-gamma regression model. This model is interpretable, parsimonious, and quick to compute. For our data, the distributional assumptions have not dramatic effect on substantive interpretation. In criminology, the mixture distribution is also of theoretical interest by its own right, and we conclude that a gamma distribution is reasonable. We emphasize the importance of comparing multiple methods in any setting where the distributional assumptions are uncertain.
Multiple murder and criminal careers: A latent class analysis of multiple homicide offenders
Forensic Science International, 2009
Purpose: To construct an empirically rigorous typology of multiple homicide offenders (MHOs). Method: The current study conducted latent class analysis of the official records of 160 MHOs sampled from eight states to evaluate their criminal careers. Results: A 3-class solution best fit the data (À2LL = À1123.61, Bayesian Information Criterion (BIC) = 2648.15, df = 81, L 2 = 1179.77). Class 1 (n = 64, class assignment probability = .999) was the low-offending group marked by little criminal record and delayed arrest onset. Class 2 (n = 51, class assignment probability = .957) was the severe group that represents the most violent and habitual criminals. Class 3 (n = 45, class assignment probability = .959) was the moderate group whose offending careers were similar to Class 2. Conclusion: A sustained criminal career with involvement in versatile forms of crime was observed for two of three classes of MHOs. Linkages to extant typologies and recommendations for additional research that incorporates clinical constructs are proffered. ß
Criminal careers and life success: new findings from the Cambridge Study in Delinquent Development
The Cambridge Study in Delinquent Development is a prospective longitudinal survey of the development of offending and antisocial behaviour in 411 males first studied at age 8 in 1961at that time they were all living in a working-class deprived inner-city area of South London. This Findings describes their criminal careers up to age 50, looking at both officially recorded convictions and self-reported offending. It also examines life success up to age 48 based on nine criteria which were also measured on a comparable basis at age 32. The main aims were to investigate the development of offending and antisocial behaviour from age 10 to age 50 and the adult life adjustment of 'persisters', 'desisters' and 'late-onset' offenders at age 48.