Typically a longitudinal growth modeling based on item response theory (IRT) requires repeated measures data from a single group with the same test design. If operational or item exposure problems are present, the same test may not be employed to collect data for longitudinal analyses and tests at multiple time points are constructed with unique…

This paper compares three methods of item calibration--concurrent calibration, separate calibration with linking, and fixed item parameter calibration--that are frequently used for linking item parameters to a base scale. Concurrent and separate calibrations were implemented using BILOG-MG. The Stocking and Lord (1983) characteristic curve method…

This study compared classical test theory (CTT) and item response theory (IRT). The behavior of the item and person statistics derived from these two measurement frameworks was examined analytically and empirically using a data set obtained from BILOG (R. Mislay and D. Block, 1997). The example was a 15-item test with a sample size of 600…

The main goal of this study was to assess how sensitive unidimensional parameter estimates derived from BILOG were when the unidimensionality assumption was violated and the underlying ability distribution was not multivariate normal. A multidimensional three-parameter logistic distribution that was a straightforward generalization of the…

The Mantel-Haenszel (MH) statistic for identifying differential item functioning (DIF) commonly conditions on the observed test score as a surrogate for conditioning on latent ability. When the comparison group distributions are not completely overlapping (i.e., are incongruent), the observed score represents different levels of latent ability…

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…

Equal percentile (EP) and partial credit (PC) equatings for raw scores from performance-based assessments with free-response items are compared through the use of data from the Maryland School Performance Assessment Program. Results suggest that EP and PC methods do not give equivalent results when distributions are markedly skewed. (SLD)

The study compares three methods for establishing cut-off scores that effect a compromise between absolute cut-offs based on item difficulty and relative cut-offs based on expected passing rates. Each method coordinates these two types of information differently. The Beuk method obtains judges' estimates of an absolute cut-off and an expected…

A mathematical model is proposed to describe how group differences in distributions of abilities, which are distinct from the target ability, influence the probability of a correct item response. In the multidimensional approach, differential item functioning is considered a function of the educational histories of the examinees. (SLD)

Four discrimination indices were compared, using score distributions which were normal, bimodal, and negatively skewed. The score distributions were systematically varied to represent the common circumstances of a military training situation using criterion-referenced mastery tests. Three 20-item tests were administered to 110 simulated subjects.…

Minimum competency cut-off scores on a statistics exam were estimated under four conditions: the Angoff judging method with item data (n=20), and without data available (n=19); and the Modified Angoff method with (n=19), and without (n=19) item data available to judges. The Angoff method required free response percentage estimates (0-100) percent,…