This article reports a study that investigated the effects of Q-matrix misspecifications on parameter estimates and misclassification rates for the deterministic-input, noisy "and" gate (DINA) model, which is a restricted latent class model for multiple classifications of respondents that can be useful for cognitively motivated diagnostic…

A concrete example is used to illustrate maximum likelihood estimation of a structural equation model with two unknown parameters. The fitting function is found for the example, as are the vector of first-order partial derivatives, the matrix of second-order partial derivatives, and the estimates obtained from each iteration of the Newton-Raphson…

The authors provide a didactic treatment of nonlinear (categorical) principal components analysis (PCA). This method is the nonlinear equivalent of standard PCA and reduces the observed variables to a number of uncorrelated principal components. The most important advantages of nonlinear over linear PCA are that it incorporates nominal and ordinal…

One of the most serious difficulties in the estimation of omega[subscript hierarchical] ([omega][subscript h]) has not been previously studied. Although it is true that one can impose a set of identifying constraints on one's solution to derive an estimate of [omega][subscript h] in the two-group factor case, there is the potential for introducing…

My dissertation contains three studies centering on the question: how to motivate people to share high quality information on online information aggregation systems, also known as social computing systems? I take a social scientific approach to "identify" the strategic behavior of individuals in information systems, and "analyze" how non-monetary…

This interview with Distinguished Science Award recipient Louis J. Gross highlights essential computational skills for modern biology, including: (1) teaching concepts listed in the Math & Bio 2010 report; (2) illustrating to students that jobs today require quantitative skills; and (3) resources and materials that focus on computational skills.

Bayesian methods for analyzing longitudinal data in social and behavioral research are recommended for their ability to incorporate prior information in estimating simple and complex models. We first summarize the basics of Bayesian methods before presenting an empirical example in which we fit a latent basis growth curve model to achievement data…

The purpose of this study was to determine the effects of an early numeracy preventative Tier 2 intervention on the mathematics performance of first-grade students with mathematics difficulties. Researchers used a pretest-posttest control group design with randomized assignment of 139 students to the Tier 2 treatment condition and 65 students to…

For a number of conceptually and practically important reasons, reporting of effect size estimates, confidence intervals, and power in parameter estimation is increasingly being recognized as the preferred approach in social science research. Unfortunately, this practice has not yet been widely adopted in the rehabilitation or general counseling…

This paper describes an empirical evaluation of a Bayesian procedure for equating scores on test forms taken by small numbers of examinees, using collateral information from the equating of other test forms. In this procedure, a separate Bayesian estimate is derived for the equated score at each raw-score level, making it unnecessary to specify a…

In this report, the authors describe the value-added models used as part of teacher evaluation systems in the District of Columbia Public Schools (DCPS) and in eligible DC charter schools participating in Race to the Top. They estimated (1) teacher effectiveness in DCPS and eligible DC charter schools during the 2011-2012 school year; and (2)…

The aim of this study was to validate an individualised measure of quality of life (WeDQoL-Goals-Thailand). Three hundred and sixty-nine Thai people completed the WeDQoL by interview. Respondents rated (0-2) the perceived necessity for wellbeing of 51 goals (goal necessity), then rated (0-3) their satisfaction with the same goals (goal…

In the signal detection paradigm, the non-parametric index of sensitivity A', as first introduced by Pollack and Norman (1964), is a popular alternative to the more traditional d' measure of sensitivity. Smith (1995) clarified a confusion about the interpretation of A' in relation to the area beneath proper receiver operating characteristic (ROC)…

This is a quantitative empirical research study validating the invariance of item difficulty parameters estimates based on the two competing measurement frameworks, the classical test theory (CTT) and the item response theory (IRT). In order to achieve the set goal, one fifty five (155) different independent samples were drawn from the population…

The purpose of this study was to empirically evaluate the impact of loglinear presmoothing accuracy on equating bias and variability across chained and post-stratification equating methods, kernel and percentile-rank continuization methods, and sample sizes. The results of evaluating presmoothing on equating accuracy generally agreed with those of…