About 45 R packages to analyze data using item response theory (IRT) have been developed over the last decade. This article introduces these 45 R packages with their descriptions and features. It also describes possible advanced IRT models using R packages, as well as dichotomous and polytomous IRT models, and R packages that contain applications…

The goal of this paper is to examine the psychometric properties of a live-coded behavioral measure of joint attention, the "Attention-Following and Initiating Joint Attention Protocol" (JA Protocol), in order to assist researchers and clinicians in identifying when this measure may meet their joint attention assessment needs. Data from…

The psychometric properties of the "Almost Perfect Scale-Revised," a test of adaptive and maladaptive aspects of perfectionist qualities, were examined with 342 academically talented middle school students. Findings indicated reliability estimates in the moderate to high range but goodness-of-fit indices were just below the criteria for…

Purpose: The purpose of the population-based study in the paper is to report on progress in formulating instruments to measure children's resilience and associated protective factors in family, primary school and community contexts. Design/methodology/approach: In this paper a total of 2,794 students, 1,558 parents/caregivers, and 465 staff were…

Extended caution indices (ECI) specify the degree of confidence that can be placed in an individual's test score by analyzing patterns of item response. Among the most promising of such indices are the standardized ECIs. Contrary to the literature, several instances were found, in a previous study, of nonnormal distributions of ECIs with samples…

A more familiar and efficient method for estimating the parameters of Cason and Cason's model was examined. Using a two-step analysis based on linear regression, rather than the direct search interative procedure, gave about equally good results while providing a 33 to 1 computer processing time advantage, across 14 cohorts of junior medical…

This paper focuses on the questions which arise as test practitioners monitor score scales derived from latent trait theory. Large scale assessment programs are dynamic and constantly challenge the assumptions and limits of latent trait models. Even though testing programs evolve, test scores must remain reliable indicators of progress.…

The stability of Rasch test item difficulty parameters was investigated under varying conditions. Data were taken from a mathematics achievement test administered to over 2,000 Australian students. The experiments included: (1) relative stability of the Rasch, traditional, and z-item difficulty parameters using different sample sizes and designs;…