Species loss revisited

Among his books are The Economics of Population Growth; Effort, Opportunity, and Wealth;and Population Matters: People, Resources, Environment, and Immigration (the latter was published by Transaction).     

Using the Delphi process to analyze social policy implementation: A post hoc case from vocational rehabilitation

This study uses a Policy Delphi to discern differences in perspective among and within groups responsible for formulating and implementing vocational rehabilitation policy. Four groups of players were chosen for our analysis: government officials, academics, directors of rehabilitation centers, and the staff who interface with program participants. Significant differences were found between the groups regarding the relative importance of possible legislative goals. This suggests that the failure of vocational rehabilitation policy to promote a work agenda may be attributed to a lack of consensus among policy implementors. The Delphi technique could help policy planners understand the different perspectives within the implementation community, and hence craft more realistic legislation.     

Estimation and Inference Are Missing Data Problems: Unifying Social Science Statistics via Bayesian Simulation

Bayesian simulation is increasingly exploited in the socialsciences for estimation and inference of model parameters. Butan especially useful (if often overlooked) feature of Bayesiansimulation is that it can be used to estimate any function ofmodel parameters, including "auxiliary" quantities such as goodness-of-fitstatistics, predicted values, and residuals. Bayesian simulationtreats these quantities as if they were missing data, samplingfrom their implied posterior densities. Exploiting this principlealso lets researchers estimate models via Bayesian simulationwhere maximum-likelihood estimation would be intractable. Bayesiansimulation thus provides a unified solution for quantitativesocial science. I elaborate these ideas in a variety of contexts:these include generalized linear models for binary responsesusing data on bill cosponsorship recently reanalyzed in PoliticalAnalysis, item—response models for the measurement ofrespondent's levels of political information in public opinionsurveys, the estimation and analysis of legislators' ideal pointsfrom roll-call data, and outlier-resistant regression estimatesof incumbency advantage in U.S. Congressional elections     

Australia: Supreme Court of Western Australia orders retrial in case of man convicted of infecting girlfriend with HIV

On 3 October 2002, the District Court convicted an HIV-positive man, Houghton, of unlawfully causing grievous bodily harm to his girlfriend for having unprotected vaginal and anal intercourse with her. Houghton had not told her of his HIV status prior to intercourse. He had been aware of his status for some years before meeting the woman, but testified at his trial that he believed that he could not transmit HIV if he did not ejaculate inside the woman. The woman became HIV-positive as a result of the sexual intercourse. The question put before the jury was twofold: whether there had been bodily injury caused by the applicant to the complainant; and whether that injury was of sufficient severity to constitute grievous bodily harm. The jury found Houghton guilty and in doing so made a finding that the transmission of HIV constitutes grievous bodily harm.     

Systematic differences in electropherogram peak heights reported by different versions of the GeneScan software

DNA profiling using STRs on the 310 and 3100 Genetic Analyzers routinely generates electropherograms that are analyzed with the GeneScan software available from the instrument's manufacturer, Applied Biosystems. Users have been able to choose from three different smoothing options that have been known to result in significant differences in the peak heights that are reported. Improvements in the underlying algorithm of the most recent version of the software also result in significant and somewhat predictable differences in peak height values. Laboratories that have performed validation studies using older versions of GeneScan should either reanalyze the data generated in those validation studies with the newest version of the software or otherwise take into consideration the systematically higher peak height values obtained as they begin following the recommendation of the manufacturer and use the new algorithm.     

Murder, Extramarital Affairs, and the Issue of Probative Value

A paper previously published in Law and Human Behavior by D. Davis and W. C. Follette (2002) argued that certain "profiling" characteristics commonly admitted into court have little or no probative value. They argued that this is especially likely to be true when the characteristic used as evidence (e.g., having an extramarital affair) is rather common in the population whereas the act in question (e.g., a man murdering his wife) is rare. Their analysis has prompted a strong response by Friedman and Park and by Kaye and Koehler with a rejoinder by Davis and Follette (all three follow this paper in this issue of Law and Human Behavior). This paper describes some of the nature of this controversy.