This article introduces a new SAS procedure written by the authors that analyzes longitudinal data (developmental trajectories) fitting mixture model. The TRAJ fits semiparametric (discrete) mixtures of censored normal, Poisson, zero-inflated and Bernoulli distributions to data. Applications psychometric scale data, offense counts, dichotomous prevalence measure in violence research are illustrated. In addition, use Bayesian information criterion address problem model selection, including...

Carnegie Mellon UniversityA developmental trajectory describes the course of a behavior over age or time. Agroup-based method for identifying distinctive groups individual trajectorieswithin population and profiling characteristics group members isdemonstrated. Such clusters might include increasers. decreasers,and no changers. Suitably defined probability distributions are used to handle 3data types—count, binary, psychometric scale data. Four capabilities dem-onstrated: (a) capability...

Group-based trajectory models are increasingly being applied in clinical research to map the developmental course of symptoms and assess heterogeneity response interventions. In this review, we provide a nontechnical overview group-based growth mixture modeling alongside sampling how these have been research. We discuss challenges associated with application both types propose set preliminary guidelines for researchers follow when reporting model results. Future directions applications...

A semi‐parametric mixture model was used with a sample of 1,037 boys assessed repeatedly from 6 to 15 years age approximate continuous distribution developmental trajectories for three externalizing behaviors. Regression models were then determine which best predicted physically violent and nonviolent juvenile delinquency up 17 age. Four identified the physical aggression, opposition, hyperactivity behavior dimensions: chronic problem trajectory, high level near‐desister moderate desister no...

This study used data from 6 sites and 3 countries to examine the developmental course of physical aggression in childhood analyze its linkage violent nonviolent offending outcomes adolescence. The results indicate that among boys there is continuity problem behavior adolescence such especially acute when early takes form aggression. Chronic during elementary school years specifically increases risk for continued violence as well other forms delinquency However, this conclusion reserved...

This article presents a group-based method to jointly estimate developmental trajectories of 2 distinct but theoretically related measurement series. The will aid the analysis comorbidity and heterotypic continuity. Three key outputs model are (a) for both series, form trajectory distinctive subpopulations; (b) probability membership in each such group; (c) joint groups across behaviors. final output offers novel features. First, probabilities can characterize linkage course Second, measure...

This article addresses three issues that are central to the criminal career debate. First, is life course of individual offending patterns marked by distinctive periods quiescence? Second, at level individual, do rates vary systematically with age? In particular, age‐crime curve single peaked or flat? Third, chronic offenders different from less active offenders? Do themselves differ in systematic ways? Using a new approach analysis careers—based on nested, mixed Poisson models which mixing...

This article is a follow-up to Jones, Nagin, and Roeder (2001), which described an SAS procedure for estimating group-based trajectory models. Group-based specialized application of finite mixture modeling designed identify clusters individuals following similar progressions some behavior or outcome over age time. has two purposes. One summarize extensions the methodology that have been developed since Jones et al. The other illustrate how lends itself presentation findings in form easily...

Physical aggression in children is a major public health problem. Not only childhood physical precursor of the and mental problems that will be visited on victims, but also aggressive themselves are at higher risk alcohol drug abuse, accidents, violent crimes, depression, suicide attempts, spouse neglectful abusive parenting. Furthermore, violence commonly results serious injuries to perpetrators themselves. Although it unusual for young harm seriously targets their aggression, studies...

Building on R. J. Sampson and H. Laub, the authors draw an analogy between changes in criminal offending spurred by formation of social bonds investment process. This conceptualization suggests that because relationships is gradual cumulative, resulting desistance will be cumulative. Using a dynamic statistical model developed D. S. Nagin K. C. Land, they test their ideas about change using yearly longitudinal data from E. Glueck Glueck's classic study careers. Their results show crime...

Evidence for a substantial deterrent effect is much firmer than it was two decades ago. However, large gaps in knowledge on the links between policy actions and behavior make difficult to assess effectiveness of options deterring crime. There are four major impediments. First, analyses must estimate not only short-term consequences but also calibrate long-term effects. Some policies that effective preventing crime short term may be ineffective or even criminogenic long run because they erode...

In explaining crime, some criminological theories emphasize time-stable individual differences in propensity to offend while others more proximate and situational factors. Using scenario data from a sample of college undergraduates we have found evidence support both positions. A measure criminal (poor self-control) was be significantly related self-reported decisions commit three offenses (drunk driving, theft, sexual assault). Even after considering self-control, there suggest that the...

Group-based trajectory models are used to investigate population differences in the developmental courses of behaviors or outcomes. This note introduces a new Stata command, traj, for fitting longitudinal data finite (discrete) mixture designed identify clusters individuals following similar progressions some behavior outcome over age time. Normal, Censored normal, Poisson, Zero-inflated and Logistic distributions supported.

The point of departure for this paper is Nagin and Land (1993), who identified four distinctive offending trajectories in a sample 403 British males—a group without any convictions, “adolescence‐limiteds,”“high‐level chronics,” “low‐level chronics.” We build upon that study with detailed analysis the distinguishing individual characteristics, behaviors, social circumstances from ages 10 through 32 these groups. most salient findings concern adolescence‐limiteds. By age work records...

Identifying and monitoring multiple disease biomarkers other clinically important factors affecting the course of a disease, behavior or health status is great clinical relevance. Yet conventional statistical practice generally falls far short taking full advantage information available in multivariate longitudinal data for tracking outcome interest. We demonstrate method called multi-trajectory modeling that designed to overcome this limitation. The generalization group-based trajectory...

We propose a model that integrates the extralegal consequences from conviction and impulsivity into traditional deterrence framework. The was tested with 252 college students, who completed survey concerning drinking driving. Key findings include following: (1) Although variation in sanction certainty severity predicted offending, celerity did not; (2) appear to be at least as great deterrent legal consequences; (3) influence of diminished an individual's “present‐orientation”; (4)...

Imprisonment is the most severe punishment in democratic societies except for capital punishment, which used only United States. Crime prevention its primary rationale. may affect reoffending various ways. It be reduced by some combination of rehabilitation and what criminologists call specific deterrence. Sound arguments can made, however, a criminogenic effect (e.g., due to antisocial prison experiences or stigma endured upon release). Remarkably little known about effects imprisonment on...

The evidence in support of the deterrent effect certainty punishment is far more consistent than that for severity punishment. However, certainty’s pertains almost exclusively to apprehension probability. Consequently, precise statement apprehension, not ensuing legal consequence, effective deterrent. This conclusion has important policy implications among which are lengthy prison sentences and mandatory minimum sentencing cannot be justified on deterrence. There four major research gaps....

The present study applied a semiparametric mixture model to sample of 284 low-income boys developmental trajectories overt conduct problems from ages 2 8. As in research on older children, 4 were identified: persistent problem trajectory, high-level desister moderate-level and low trajectory. Follow-up analyses indicated that initially high groups differentiated early childhood by child fearlessness elevated maternal depressive symptomatology. Persistent rejecting parenting. implications the...

This article provides an overview of a group-based statistical methodology for analyzing developmental trajectories - the evolution outcome over age or time. Across all application domains, this method lends itself to presentation findings in form easily understood graphical and tabular data summaries. In so doing, researchers with tool figuratively painting portrait predictors consequences distinct development. Data summaries have great advantage being accessible nontechnical audiences...

In a prior study, we identified 4 groups following distinct developmental courses, or trajectories, of physical aggression in 1037 boys from 6 to 15 years age high-risk population sample Montréal, Québec. Two were trajectories high aggression, persistently group and but declining group. The other 2 low moderate This study early predictors ages years.In this logistic regression analysis was used identify parental child characteristics that distinguished trajectory membership.For displaying...