This study examines a case management intervention for first-time pregnant and parenting adolescents. It compares a sample of 1,260 first-time adolescent mothers in the Adolescent Parenting Program (APP) in North Carolina with 1,260 first-time adolescent mothers who did not participate in the program (non-APP). Using birth certificate data,…

Comparing variability of test scores across alternate forms, test conditions, or subpopulations is a fundamental problem in psychometrics. A confidence interval for a ratio of standard deviations is proposed that performs as well as the classic method with normal distributions and performs dramatically better with nonnormal distributions. A simple…

Research on markets and marketing of some non-timber forest products (NTFPs) was carried out in selected locations of Osun State. The NTFPs considered are chewing sticks such as "Massularia acuminata" and bush meat like "Thryonomys swinderianus", representing both the flora and fauna aspects of NTFPs, respectively. Five Local…

Students in four sections of an undergraduate educational course (two large and two small sections) took out-of-class practice exams prior to actual exams for each of five course units. Each course unit consisted of five class sessions focusing on a specific developmental theme. Some sections received practice-exam credit based on the number of…

This study compares the classification accuracy of linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), logistic regression (LR), and classification and regression trees (CART) under a variety of data conditions. Past research has generally found comparable performance of LDA and LR, with relatively less research on QDA and…

Part of the history of oil and gas development on Indian reservations concerns potential underpayment of royalties due to under-valuation of production by oil companies. This paper discusses a model used by the Shoshone and Arapaho tribes in a lawsuit against the Federal government, claiming the Government failed to collect adequate royalties.…

The effect of child care regulations on outcomes in the child care market and the labor market for mothers of young children is examined. The analysis uses a time series of cross sections and examines the robustness of previous cross-section findings to controls for state-level heterogeneity. Child care regulations as a group have statistically…

Seance-room and other large-scale psychokinetic phenomena have fascinated humankind for decades. Experimental research has reduced these phenomena to attempts to influence (a) the fall of dice and, later, (b) the output of random number generators (RNGs). The meta-analysis combined 380 studies that assessed whether RNG output correlated with human…

The longitudinal stability of eating problems and their relationships to risk factors were investigated in a representative population sample of 623 Norwegian girls aged 13-14 followed over 7 years (3 time points). Three eating problem symptoms were measured: Restriction, Bulimia-food preoccupation, and Diet, all taken from the 12-item Eating…

This report discusses school enrollment levels and trends in the population aged 3 and older based on data collected in 2006 by the U.S. Census Bureau in the American Community Survey (ACS) and the Current Population Survey (CPS). Historically, the CPS has been the only data source used to produce school enrollment reports. This is the first…

Experiments that assign intact groups to treatment conditions are increasingly common in social research. In educational research, the groups assigned are often schools. The design of group-randomized experiments requires knowledge of the intraclass correlation structure to compute statistical power and sample sizes required to achieve adequate…

The development and evaluation of methods for detecting potentially biased items or differentially functioning items (DIF) represent a critical area of research for psychometricians because of the negative impact of biased items on test validity. A summary is provided of the authors' 12 years of research at the University of Massachusetts…

The use of indices and statistics based on nonlinear factor analysis (NLFA) has become increasingly popular as a means of assessing the dimensionality of an item response matrix. Although the indices and statistics currently available to the practitioner have been shown to be useful and accurate in many testing situations, few studies have…

The purpose of this study was to compare two non-parametric procedures, the Mantel-Haenszel (MH) procedure and the simultaneous item bias (SIB) procedure, with respect to their Type I error rates and power, and to investigate the conditions under which asymptotic distributional properties of the SIB and MH were obtained. Data were simulated to…

Though common structural equation modeling (SEM) methods are predicated upon the assumption of multivariate normality, applied researchers often find themselves with data clearly violating this assumption and without sufficient sample size to use distribution-free estimation methods. Fortunately, promising alternatives are being integrated into…