When the underlying responses are on an ordinal scale, gamma is one of the most frequently used indices to measure the strength of association between two ordered variables. However, except for a brief mention on the use of the traditional interval estimator based on Wald's statistic, discussion of interval estimation of the gamma is limited.…

The regression trunk approach (RTA) is an integration of regression trees and multiple linear regression analysis. In this paper RTA is used to discover treatment covariate interactions, in the regression of one continuous variable on a treatment variable with "multiple" covariates. The performance of RTA is compared to the classical…

Weekly cycles in emotion were examined by combining item response modeling and spectral analysis approaches in an analysis of 179 college students' reports of daily emotions experienced over 7 weeks. We addressed the measurement of emotion using an item response model. Spectral analysis and multilevel sinusoidal models were used to identify…

In the context of item response theory, it is not uncommon that person-by-item data are correlated beyond the correlation that is captured by the model--in other words, there is extra binomial variation. Heterogeneity of the parameters can explain this variation. There is a need for proper statistical methods to indicate possible extra…

In their reply to our article, Greenwald, Rudman, Nosek, and Zayas offered comments on the use of their procedure relative to one that focuses on standard multiple regression (SMR) methods). Here we address five issues where we think a balance of perspective is called for: (a) issues of measurement, (b) the structuring and reporting of the…

This study compared vertical scaling results for the Rasch model from BILOG-MG and WINSTEPS. The item and ability parameters for the simulated vocabulary tests were scaled across 11 grades; kindergarten through 10th. Data were based on real data and were simulated under normal and skewed distribution assumptions. WINSTEPS and BILOG-MG were each…

Study of the effect of transitions on individual and family outcomes is central to understanding families over the life course. There is little consensus, however, on the appropriate statistical methods needed to study transitions in panel data. This article compares lagged dependent variable (LDV) and change score (CS) methods for analyzing the…

One theoretical feature that makes item response theory (IRT) models those of choice for many psychometric data analysts is parameter invariance, the equality of item and examinee parameters from different examinee populations or measurement conditions. In this article, using the well-known fact that item and examinee parameters are identical only…

We propose a computational model of the emergence of gaze following skills in infant-caregiver interactions. The model is based on the idea that infants learn that monitoring their caregiver's direction of gaze allows them to predict the locations of interesting objects or events in their environment (Moore & Corkum, 1994). Elaborating on this…

Evaluation professionals can benefit from practice in the same way that lawyers, doctors, and other professionals improve their performance through practice. The case method enables practice through role plays and situational analyses. Cases provide openings for evaluators and program planners to experiment with new norms of communication…

Objective: To compare simulator-based teaching with traditional instruction among clinical medical students. Methods: Randomized controlled trial with written pre-post testing. Third-year medical students (n = 38) received either a myocardial infarction (MI) simulation followed by a reactive airways disease (RAD) lecture, or a RAD simulation…

The 1992 NIH Research Planning Conference on Prosthetic and Orthotic Research for the 21st Century (Childress, 1992) recognized that the field of prosthetics lacks theoretical understanding and empirical studies on learning to control an upper-extremity prosthesis. We have addressed this problem using a novel approach in which persons without…

In this paper, a didactical proposal is presented to introduce the variational methods for solving boundary value problems to engineering students. Starting from a couple of simple models arising in linear elasticity and heat diffusion, the concept of weak solution for these models is motivated and the existence, uniqueness and continuous…

Virtual flight can be very entertaining, and computer-based simulators can also be educational, if organized and used correctly. When Berea College decided to find a flight simulator suited to the school's educational goals, the faculty settled on an ANT-18 Link trainer. This article begins with a discussion of Link trainers' history, and then…

Sportsmanship is a component that is increasingly missing in youth sports. Negative experiences resulting from poor sportsmanship may lead children to limit their participation in sports or drop out all together. Parks, recreation, and tourism professionals may look to systems modeling to help develop programs and policies in the hope of…