The Behavioral Effects of Environmental Regimes: Collective-Action vs. Social-Practice Models

International Environmental Agreements: Politics, Law and Economics - Most observers agree that institutions play significant roles both in causing and in confronting large scale environmental...     

How you can tell if the simulations in computational criminology are any good

Computational criminology applies computer simulations to study topics of interest for criminologists. Just as for all computer modelling in science, the validity of the simulations ultimately depends on whether they are able to reproduce empirical phenomena with sufficient accuracy. The only way in which this can be determined is by comparing model output to real observations. This paper provides an overview of how such model evaluations can be undertaken.

中国汉族女性青少年法医学活体骨龄推断数学模型的建立

目的建立推断中国汉族女性青少年活体骨龄的数学模型。方法摄取华中、华南及华东等地区的838名年龄介于11～20周岁正常女性青少年双侧锁骨胸骨端以及左侧肩、肘、腕、髋、膝、踝关节的X线片。依据青少年骨发育分级标准对24项骨骼发育指标进行阅片、分级,结合考虑身高、体质量及地区等影响因素．应用SAS8．1及SPSS11．0软件进行统计学处理,探索各指标与年龄的相关性。结果建立了我国汉族女性青少年利用锁骨胸骨端及6大关节骨骺闭合程度联合推断活体年龄的多元回归数学模型．推导出判定我国汉族女性青少年是否已满14、16和18周岁的Fisher’S两类判别分析方程。结论本研究所建立的判定活体年龄的数学模型丰富了活体年龄的法医学鉴定方法,有利于提高活体骨龄鉴定方法的科学性和结论的准确性。     

Estimation of arrest careers using hierarchical stochastic models

This paper introduces a general procedure using hierarchical stochastic models for characterizing criminal careers within a population of heterogeneous offenders. Individuals engage in criminal careers which are treated as stochastic processes governed by fixed parameters (e.g., a rate parameter), and these parameters come from specified distributions. The parameters of these distributions at the upper level of the hierarchy must then be specified. The models are estimated using data on all persons arrested at least once in the six-county Detroit Standard Metropolitan Statistical Area during the 4 years 1974–1977 for a criterion offense (an index crime other than larceny) and arrested at least once for robbery through April 1979. The collected data set is not a random sample of all such offenders in the population. There is a bias toward selecting those with a higher arrest frequency. In order to make more general inferences, statistical adjustment was needed to overcome the arrest-frequency sampling bias. We construct a series of models for the arrest career and fit the models with the data set of arrests. After correcting biases in the data, we estimate the model parameters using empirical Bayes methods and then examine the resulting models.     

Developmental explanations of delinquent behavior among siblings: Common factor vs. transmission mechanisms

We compare the statistical fit of two developmental explanations of delinquent behavior using longitudinal sibling data. The transmission effects model relates future delinquency to prior delinquency, delayed sibling effects, and unique environment. The common-factor effects model adds to these influences a latent variable representing persistent causes shared by siblings. These two models were fit to longitudinal data on 470 sibling pairs interviewed on three occasions. The common-factor effects model fit the data more closely than the transmission model. Nonmutually exclusive interpretations of the common effects model include (a) personality dispositions and (b) unchanging aspects of the social environment such as concurrent sibling effects and siblings' common friends.     

Growth curves of deviant behavior in early adolescence: A multilevel analysis

Multilevel growth curve models provide a means of analyzing individual differences in the growth of deviance, allow a number of theories to be integrated in a single model, and can help to unify research on deviant/delinquent/criminal careers at different stages of the life cycle. Building on the distinction between population heterogeneity and state dependence as alternative explanations of persistent individual differences in deviance (Heckman, 1981; Nagin and Paternoster, 1991), we show that models with two levels can be used to represent and analyze a variety of criminological theories. The first level (level 1) uses repeated measurements on individuals to estimate individual-level growth curves. The second level treats the level 1 growth curve parameters (e.g., slope, intercept) as outcome variables and uses time-invariant factors to explain variation in these parameters across individuals. We illustrate this approach by estimating a model of growth in deviance drawn from Gottfredson and Hirschi's deviant propensity theory. An innovative feature is the assumption that adolescents' expected growth curves of deviance follow a classical Pearl-Verhulst logistic growth model (Pearl, 1930). The results suggest that five risk factors—parental psychiatric problems, lack of parental support, living arrangements with zero or one parent in residence, low family income, and male gender—have strongly positive effects on deviant propensity. For example, adolescents with no supportive parents, and no other risk factors, have expected asymptotic levels of deviance (peak levels attained at about age 18) that are about twice as high as those of adolescents with no risk factors. Yet more than two-thirds of the individual-level variability in growth curves is unexplained by the five risk factors. This unobserved heterogeneity would remain hidden in analyses using conventional structural equations models and the same explanatory variables.     

京族经济发展模式变迁及启示

党和政府一直关注人口较少民族的发展,出台一系列的政策措施推进人口较少民族的发展.京族是22个人口较少民族之一,伴随着广西壮族自治区成立50周年的步伐,已经从贫困落后步入了富裕文明,总结其经济发展的经验教训,对其他民族地区经济的发展有较高的理论价值和现实意义.     

形式模型与国际关系研究

本文讨论了形式模型在国际关系中的应用,认为形式模型对国际关系研究能够产生助益,这主要体现在:通过明晰理论假设,使人们对结论的适用范围有清楚的认识;使研究人员能够对研究对象中涉及的机制进行清晰可靠的分析;通过模型序列,促进知识的积累;避免研究过程中的反复重新论证等等。在此基础上,本文沿着理性选择、集体选择和博弈论的发展线索对形式模型在国际关系领域的应用进行了讨论。     

THE ROLE OF RACE AND ETHNICITY IN PAROLE DECISIONS*

The parole board plays an integral part in the reentry of offenders into the community from prison in most states; yet, little is known about the decision‐making practices of this group. In particular, few studies have used quantitative data to examine parole among a large group of offenders, and less is known about the direct and joint effects of race and ethnicity on this decision point. We extend previous work by considering variation in parole timing among a sample of young, serious offenders incarcerated in one state. Results from a series of proportional hazard models reveal substantial variation in parole timing. Consistent with the existing theoretical research on parole, parole actors are most concerned with community protection and heavily weigh measures of the current offense, institutional behavior, and the official parole guidelines score. The direct effects of race and ethnicity were also revealed. Black offenders spent a longer time in prison awaiting parole compared with white offenders, and the racial and ethnic differences are maintained net of legal and individual demographic and community characteristics. These findings provide important insight into the parole process and augment the existing theoretical work on disparities in decision making.     

THE RELATIONSHIP BETWEEN SELF‐CONTROL AND LANGUAGE: EVIDENCE OF A SHARED ETIOLOGICAL PATHWAY*

Converging lines of research suggest that self‐control and language may be inextricably linked. No empirical research has ever examined this proposition, however. We address this gap in the literature by analyzing a sample of twin pairs from a nationally representative data set of children. The results revealed three broad findings. First, diminished language skills were predictive of low self‐control both cross‐sectionally and longitudinally. Second, the covariation between language and self‐control was linked to both genetic and environmental factors. Third, after controlling for genetic influences on self‐control, language skills were predictive of variation in individual levels of self‐control. The theoretical implications of these findings are discussed.