The Statistical Properties and Empirical Performance of Double Regression

Voting rights litigation requires ecological inference to estimatethe voting preferences of minority and nonminority groups withinthe electorate. Double regression has been the procedure mostcommonly employed for this purpose. This article presents thefirst formal examination of this procedure. The underlying structuralmodel reveals that double regression estimators are neitherunbiased nor consistent estimators of true within-group votepreferences or polarization. Simulations demonstrate that theycan substantially exaggerate the differences between minorityand nonminority vote choices when none are present, and dramaticallyunderstate them when differences exist. In sum, double regressioncannot meet conventional statistical standards for reliability.Consequently, it should be abandoned.     

Sentencing Using Statistical Treatment Rules: What We Don’t Know Can Hurt Us

The existing literature seriously misinterprets the available evidence on the predictability of high rate criminal offending and thus the potential value of statistical treatment rules that impose stiffer punishments on offenders with higher predicted risk of recidivism. The misinterpretation results from the failure to take account of the fact that the data used in existing risk assessment exercises come from environments characterized by informal (and sometimes formal) attempts by judges and other actors to base penal treatments on expected recidivism. Findings of little or no predictive power for baseline covariates may simply indicate the efficient use of the available information. We lay out the problem in detail, provide examples from several literatures and then consider general solutions to the problem.

Social disorganization, Latinos and juvenile crime in the Texas borderlands

Purpose

Using a time-series cross-sectional design, we estimated the effects of social disorganization on juvenile property crime rates in a predominately Latino, Texas-Mexico border region.

Methods

Eighteen years of data from seven independent sources (Bureau of Economic Analysis, Bureau of Labor Statistics, Census Bureau, Texas State Demographer, Internal Revenue Service, Department of Agriculture Economic Research Service, and Uniform Crime Reports) were examined. Counties were utilized as the unit of analysis, and time-series cross-sectional regression models were estimated.

Results

The analysis showed that per capita income was negatively related to juvenile crime in both rural and urban counties. Ethnic heterogeneity was positively related to the outcome in rural, but not urban, counties; while percent foreign-born was negatively related to juvenile crime in urban, but not rural, counties.

Conclusions

The Latino experience, both native- and foreign-born, is important for improving our understanding how economic and social conditions relate to crime. Comparative analyses between distinct geographical environments, such as rural and urban counties, can yield insight how the local context interacts with social disorganization processes.     

A test for carrion fly full siblings: a tool for detecting postmortem relocation of a corpse

We propose a genetic test for full sibship for a pair of carrion flies that could reveal the postmortem relocation of a corpse. A carrion fly larva is sometimes left behind when a corpse is moved. The discovery of full sibling larvae of approximately the same developmental stage at two locations would strongly suggest that a corpse was moved between those two sites. Distributions of pairwise comparisons of relatedness (R) coefficients were generated using amplified fragment length polymorphism profiles for nine samples of laboratory-generated full siblings as well as for a reference sample of nonfull sibling Phormia regina (Diptera: Calliphoridae). The mean relative R coefficient, a pairwise measure of the proportion of shared alleles, was 0.479 (±0.289 SD) for full siblings, close to the theoretical expectation of 0.5. A likelihood ratio (LR) test was based on observed distributions of R. R >0.55 corresponded to an LR >1000 favoring full sibship for that pair of individuals.