Forecasting highway casualties: The British road safety act and a sense of déja vu

This paper reexamines the effect of the introduction of the British Road Safety Act of 1967. We construct a dynamic model relating monthly road casualties to road traffic, rainfall, and alcohol consumption, standardizing for the seasonality in the data. An intervention variable captures the effect of the Road Safety Act. The findings confirm Ross's earlier conclusion that the Road Safety Act significantly reduces casualties. However, we find that the Road Safety Act only accounts for 2.7 percent of the variance in road casualties, while miles-driven and rainfall account for 48.8 percent, and alcohol consumption explains 4.2 percent. Our model forecasts accurately for 24 months beyond December, 1972, the last month used for estimation.     

The influence of police interventions and alternative income sources on the dynamic process of choosing crime as a career

This paper demonstrates how a rational process of choice may be influenced by both deterrence forces and economic opportunities. This choice is modeled by a dynamic (Markov) process which captures self-sorting by youth among the categories of innocents, desisters, and persisters. in crime. A key to the results is the introduction of the perceived probability of punishment and its influence on the sorting process. The analysis shows how this force and the availability, or lack of, economic opportunities or income sources modify transition probabilities. The long-run consequences will be a larger subpopulation of individuals who have experimented with crime but subsequently revert to crime-free behavior and a smaller subpopulation of individuals who commit a greater share of crime. Empirical evidence is based on data from the New Youth Cohort of the National Longitudinal Surveys.     

Risk assessment in offenders with mental disorders: relative efficacy of personal demographic, criminal history, and clinical variables

Following the meta-analysis by Bonta, Law, and Hanson, (1998) this study examined the ability of personal demographic, criminal history, and clinical variables to predict reoffending in offenders in the United Kingdom who had mental disorders. The efficacy of each variable in predicting rate of general reoffending and violent reoffending was investigated. Age on admission, number of days hospitalized, and number of previous offenses were the most effective variables in predicting re-offending, with number of previous offenses being the strongest predictor. Clinical diagnosis was not predictive of reoffending when the variance attributable to these other predictors was controlled for. None of the variables were able to discriminate between general offenders and violent offenders indicating that the same variables predict both types of reoffending. The results showed that reconviction in offenders with mental disorders can be predicted using the same criminogenic variables that are predictive in offenders without mental disorders.     

A study of mutation rates and the characterisation of intermediate, null and duplicated alleles for 13 Y chromosome STRs

Previously reported Y chromosome STR haplotype databases for three UK population groups, plus additionally analysed samples, have been scrutinised for the presence of non-standard (intermediate, null and duplicated) alleles. These alleles have been characterised by sequencing, some showing changes in the repeat structure, and the frequencies reported. Mutation rates for each of the 13 STRs have been calculated when analysis of father-son pairs has been possible. An example illustrating the use of non-standard alleles in a large family tree is outlined.