Sample Selection in Models of Academic Performance

This article shows how admission and enrollment processes affect the interpretation of simple validation studies of academic performance. In a competitive market for students, optimal behavior of admissions committees and applicants drives the simple correlation between test scores and performance toward zero, regardless of the relationship in the population of prospective students. Data from our university's MBA program support the prediction that applicants exhibit a higher correlation between test scores and undergraduate GPAs than do current students. This suggests that standard validation studies will understate the importance of GMAT scores in predicting performance of potential MBA students. (JEL C24 , I121 , C52 )     

The frisch-waugh theorem and generalized least squares

We discuss the standard linear regression model with nonspherical disturbances, where some regressors are annihilated by considering only the residuals from an auxiliary regression, and where, analogous to the Frisch-Waugh procedure, the original GLS procedure is applied to the transformed data. We call this procedure pseudo-GLS and give conditions for pseudo-GL5 to be equal to genuine GLS. We also show via examples that these conditions are often violated in empirical applications, and that the Frisch-Waugh Theorem still “works” with nonspherical disturbances if efficient estimation is applied to both the original and the transformed data.     

„Zu allem fähig“

Ohne Zusammenfassung     

A Rank-Sum-Type Test for Paired Data with Multiple Endpoints

Clinical trials and other types of studies often examine the effects of a particular treatment or experimental condition on a number of different response variables. Although the usual approach for analysing such data is to examine each variable separately, this can increase the chance of false positive findings. Bonferroni's inequality or Hotelling's T² statistic can be employed to control the overall type I error rate, but these tests generally lack power for alternatives in which the treatment improves the outcome on most or all of the endpoints. For the comparison of independent groups, O'Brien (1984) developed a rank-sum type test that has greater power than the Bonferroni and T² procedures when one treatment is uniformly better (i.e. for all endpoints) than the other treatment(s). In this paper we adapt the rank-sum test to studies involving paired data and demonstrate that it, too, has power advantages for such alternatives. Simulation results are described, and an example from a study measuring the effects of sleep loss on glucose metabolism is presented to illustrate the methodology.     

REGION, RELIGIOUS COMMITMENT, AND LIFE SATISFACTION AMONG BLACK AMERICANS

Using data from the National Survey of Black Americans (NSBA), this research examines three sets of hypotheses regarding the effects of religious commitment on life satisfaction. Further, given evidence of historical geographical differences in black culture and social structure, this study explores the regional specificity of religious influences on life satisfaction. Religious participation contributes to subjective well-being only among non-southern blacks, while private religiosity is unrelated to well-being in any analysis. There are also denominational effects: non-southern members of traditional black denominations (i.e., Baptists and Methodists) and southern Catholics report particularly high levels of life satisfaction. In addition, the effects of religion on life satisfaction are contingent upon age for non-southerners only. This study concludes with a discussion of directions for future research on religion and mental health.     

The Effects of Perceived Barriers,Role Models,and Acculturation on the Career Self‐Efficacy and Career Consideration of Hispanic Women

This study used path analysis to examine the relationship between perceived barriers, acculturation, and role model influence on the career self‐efficacy and career considerations of a sample of Hispanic women. Two path models were examined. The male‐dominated model accounted for 15% of the variance, and the female‐dominated model accounted for 26% of the variance. No relationship was found between the variables of interest and male‐dominated career self‐efficacy and consideration. However, perceived barriers were related to female‐dominated career consideration and Anglo acculturation significantly contributed to female‐dominated career self‐efficacy. Results are discussed with regard to career practice and research with Hispanic women.     

Mixing patterns between age groups in social networks

We present a method for estimating transmission matrices that describe the mixing and the probability of infection between age groups. Transmission matrices can be used to estimate age-dependent forces of infection in age-structured, compartmental models for the study of infectious diseases. We analyze the social network generated by the synthetic population of Portland and extract mixing patterns. Our results show that the mixing within the population consists of two groups, children and adults. Children interact most frequently with other children close to their own age, while adults interact with a wider range of age groups and the durations of typical adult contacts are shorter than typical contacts between children. Furthermore, the transmission matrix shows that children are more likely to acquire infection than adults.     

Suicide prevention and intervention with young people in foster care in Canada

Given the history of turmoil in their lives, foster children and young people coming into care are particularly at risk of suicide. Whether a crisis is successfully prevented, or treated and transcended, depends upon the ability of foster parents and agency staff members to understand the nature of the situation and to work together in dealing with it.     

Practice and Research in Career Counseling and Development—2002

The authors present a review of the 2002 career development literature. The literature review is divided into the following areas: career theory, career assessment, career counseling interventions and practice, career counseling training and professional issues, and international issues in career counseling. The authors discuss the implications of the findings in this literature for career counseling practice.