Economic models of incentives in employment relationships are based on a specific theory of motivation: employees are "rational cheaters," who anticipate the consequences of their actions and shirk when the marginal benefits exceed costs. We investigate the "rational cheater model" by observing...

This article reports on an extension of group-based trajectory modeling to address nonrandom participant attrition or truncation due to death that varies across trajectory groups. The effects of the model extension are explored in both simulated and real data. The analyses of simulated data...

Recent theoretical and empirical work in criminology supports the classification of individuals in criminal groups, where groups differ in the determinants of antisocial behavior and resulting trajectories of offending over time. This article presents methods for finding distinctions between...

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 trajectory is a specialized application of finite mixture modeling and is designed to identify clusters of individuals following similar...

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 to longitudinal data finite (discrete) mixture models designed to identify clusters of individuals...

Previous methodological research has shown that hidden heterogeneity in hazard rate regression models—in the form of systematic differences between sample members in the risk or hazard of making a transition due to unobserved variables not accounted for by the measured...

This article introduces a new SAS procedure written by the authors that analyzes longitudinal data (developmental trajectories) by fitting a mixture model. The TRAJ procedure fits semiparametric (discrete) mixtures of censored normal, Poisson, zero-inflated Poisson, and Bernoulli distributions...

Specifications and moment properties of the univariate Poisson and negative binomial distributions are briefly reviewed and illustrated. Properties and limitations of the corresponding poisson and negative binomial (gamma mixtures of Poissons) regression models are described. It is shown how a...

This article reviews the evidence on the deterrent effect of police, imprisonment, and capital punishment and additionally summarizes knowledge of sanction risk perceptions. Studies of changes in police presence, whether achieved by changes in police numbers or in their strategic deployment,...