A method for calculating the strength of evidence associated with an earwitness's claimed recognition of a familiar speaker

The present paper proposes and demonstrates a method for assessing strength of evidence when an earwitness claims to recognize the voice of a speaker who is familiar to them. The method calculates a Bayes factor that answers the question: What is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was the suspect versus what is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was not the suspect but some other speaker from the relevant population? By “claim” we mean a claim made by a cooperative earwitness not a claim made by an earwitness who is intentionally deceptive. Relevant data are derived from naïve listeners' responses to recordings of familiar speakers presented in a speaker lineup. The method is demonstrated under recording conditions that broadly reflect those of a real case.     

Score based procedures for the calculation of forensic likelihood ratios – Scores should take account of both similarity and typicality

Score based procedures for the calculation of forensic likelihood ratios are popular across different branches of forensic science. They have two stages, first a function or model which takes measured features from known-source and questioned-source pairs as input and calculates scores as output, then a subsequent model which converts scores to likelihood ratios. We demonstrate that scores which are purely measures of similarity are not appropriate for calculating forensically interpretable likelihood ratios. In addition to taking account of similarity between the questioned-origin specimen and the known-origin sample, scores must also take account of the typicality of the questioned-origin specimen with respect to a sample of the relevant population specified by the defence hypothesis. We use Monte Carlo simulations to compare the output of three score based procedures with reference likelihood ratio values calculated directly from the fully specified Monte Carlo distributions. The three types of scores compared are: 1. non-anchored similarity-only scores; 2. non-anchored similarity and typicality scores; and 3. known-source anchored same-origin scores and questioned-source anchored different-origin scores. We also make a comparison with the performance of a procedure using a dichotomous “match”/“non-match” similarity score, and compare the performance of 1 and 2 on real data.     

Family profiles of adaptability,cohesion, and communication for learning handicapped and nonhandicapped adolescents

The family functioning of 30 nonhandicapped and 30 learning handicapped adolescents and their parents was examined. Measures of adaptability, cohesion, and communication were taken from the parent and the adolescent perspectives. Parent and adolescent perspectives on these areas of functioning were analyzed with a cluster analytic technique, which resulted in five distinct profiles of family functioning. These statistical groupings were confirmed by information gathered through participant observation from an accompanying investigation. The nature of the five clusters confirmed the existence of similar family functioning across the nonhandicapped and learning handicapped groups. Additionally, variations in reaction and adjustment to the amount of structure in the family environment by different families was documented. The importance of considering adolescent and parent perspectives separately was highlighted.Received degree from University of California, Riverside. Research interests are in the area of the social development of at-risk or mildly handicapped children and adolescents in school and family settings.Received degree from Teachers College, Columbia University. Research interests in social competence and family relations of learning handicapped populations as well as the development of family, community, and school partnerships.     

Natural resources, aid, and democratization: A best-case scenario

Natural resources and aid give dictators revenue to maintain power. Attempts are being made, therefore, to funnel these resources away from nondemocratic governments and toward their citizens. Using formal analysis and building on existing theories of democratization, I analyze the effects of such institutional solutions when they function perfectly (the best-case scenario). The models show that even with institutional safeguards, these resources diminish chances for democratization. In addition to their practical importance, the results have an important theoretical implication: the political resource curse may not be due to dictators' use of these resources, but simply to their existence in nondemocracies.     

The Role of Protective Factors in Supporting the Academic Achievement of Poor African American Students During the Middle School Transition

In this study of 62 African American families living in poverty, we examined the main and interactive effects of psychological, family, and school factors on students' grade point average across the middle school transition. Both parent interviews and student surveys were collected, resulting in three major findings. First, students experienced a significant decline in grade point average across the transition from elementary to middle school. Second, students who felt more academically efficacious had higher grade point averages across the transition than did their peers. Third, significant interactions were found between family and school factors. These results suggest that rather than focusing exclusively on either parental involvement or the school environment, the combination of both family and school factors may be most effective in supporting the academic achievement of poor African American students during the transition to middle level schools.     

Allele frequencies for 15 autosomal STR loci and admixture estimates in Puerto Rican Americans

Allelic frequencies of 15 short tandem repeats (STR) markers (CSF1PO, FGA, THO1, TPOX, VWA, D3S11358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, D19S433 and D2S1338) were determined using the AmpFl STR Identifiler PCR Amplification Kit in Puerto Rican American individuals (N=205) from Massachusetts. The FGA, D18S51 and D2S1338 loci had a high power of discrimination (PD) with values of 0.967, 0.965 and 0.961, respectively. Significant deviations from the Hardy-Weinberg (HW) equilibrium were not detected. An important genetic contribution of Caucasian European (76.4%) was detected in Puerto Rican Americans. However, comparative analysis between Puerto Rican American and other neighboring populations from United States mainly with African and Caucasian Americans, revealed significant differences in the distribution of STR markers. Our results are important for future comparative genetic studies of different American ethnic groups, in particular a cultural group called Hispanic-Americans and should be helpful for forensic and paternity testing.