Analyzing Multiple-Item Measures of Crime and Deviance I: Item Response Theory Scaling

Multiple-item measures of self-reported offending typically provide the principal outcome measures for individual level research on the causes of crime and deviance. This article directs attention to the substantial problems presented by the task of forming composite scores for these measures, and it presents a possible solution to those problems. We consider scaling by means of the graded response model from item response theory (IRT) as a potential means of overcoming the shortcomings of traditional summative scaling and of obtaining valuable information about the strengths and weaknesses of our measures. We illustrate this strategy through a scale analysis of a fourteen-item, self-report measure of delinquency, using three years of data from the Monitoring the Future study, an annual national survey of high school seniors. The graded response model proves to be consistent with the data, and it provides results that address important substantive questions about self-report measures. The findings are informative about the strengths and weaknesses of alternative strategies for developing self-report instruments, indicating that there is little to be gained by making fine distinctions in the frequency of individual delinquent acts.     

Race and Ethnicity in Medical Research: Requirements Meet Reality

Race and ethnicity are commonly reported variables in biomedical research, but how they were determined is often not described and the rationale for analyzing them is often not provided. JAMA improved the reporting of these factors by implementing a policy and procedure. However, still lacking are careful consideration of what is actually being measured when race/ethnicity is described, consistent terminology, hypothesis-driven justification for analyzing race/ethnicity, and a consistent and generalizable measurement of socioeconomic status. Furthermore, some studies continue to use race/ethnicity as a proxy for genetics. Research into appropriate measures of race/ethnicity and socioeconomic factors, as well as education of researchers regarding issues of race/ethnicity, is necessary to clarify the meaning of race/ethnicity in the biomedical literature.     

Identification of fentanyl derivatives

An interpretative approach to the identification of fentanyl homologs and analogs is presented. The techniques employed are liquid/liquid extractions; capillary gas chromatography; and infrared, mass, and nuclear magnetic resonance spectral characterization. Spectral data are presented for eight fentanyl derivatives of clandestine origin.     

Determination of carbon monoxide in blood by gas chromatography using a thermal conductivity detector

A method is described for the gas chromatographic quantitation of carbon monoxide by means of thermal conductivity detection. Carbon monoxide is released from blood samples as small as 0.02 mL using a unique extraction chamber. The method was compared to a standard gas chromatographic and spectrophotometric method of carbon monoxide quantitation. It was comparable to the former with all samples evaluated and apparently more reliable than the latter with decomposed samples.     

An enzyme-linked immunosorbent assay (ELISA) for trinitrotoluene (TNT) residue on hands

An enzyme-linked immunosorbent assay (ELISA) developed for the detection of trinitrotoluene (TNT) in munitions wastewater has been adapted to the detection of TNT residue on hands following contact. Using the procedure developed, as little as 50 pg of TNT could be detected. Accounting for sample size and dilution, the 50 pg equates to 15 ng of TNT recovered from the hands. Following contact with TNT, amounts ranging from 53 ng to more than 1500 ng were recovered from hands. The monoclonal anti-TNT antibodies showed no cross-reactivity with several other explosives or common contaminants. These preliminary results indicate promise for the development of a simple-to-use, immunoassay-based field test kit for TNT and, ultimately, other explosives.