Educational software games aim at increasing the students' motivation and engagement while they learn. However, if software games are targeted to school classrooms they have to be usable and likeable by all students. Usability of virtual reality games may be a problem because these games tend to have complex user interfaces so that they are more…

The effect of violating the assumption of nonspeededness on ability and item parameter estimates in item response theory was studied through simulation under three speededness conditions. Results indicate that ability estimation was least affected by speededness but that substantial effects on item parameter estimates were found. (SLD)

Previous research examining the effects of reducing the number of score groups used in the matching criterion of the Mantel-Haenszel procedure, when screening for differential item functioning, has produced ambiguous results. The goal of this study was to resolve the ambiguity by examining the problem with a simulated data set. The main results…

The capability of the DIMTEST statistical test to assess essential dimensionality of the model underlying item responses of real tests as opposed to simulated tests was investigated. A variety of real test data from difference sources was used to assess essential dimensionality. Based on DIMTEST results, some test data are assessed as fitting an…

A statistical procedure is presented that is designed to test for unidirectional test bias existing simultaneously in several items of an ability test, based on the assumption that test bias is incipient within the two groups' ability differences. The proposed procedure--Simultaneous Item Bias (SIB)--is based on a multidimensional item response…

Smallest exact confidence intervals for the ability parameter of the Rasch model are derived and compared to the traditional asymptotically valid intervals based on Fisher information. Tables of exact confidence intervals, termed Clopper-Pearson intervals, can be drawn up with a computer program developed by K. Klauer. (SLD)

In a simulation study of ability and estimation of differential item functioning (DIF) in computerized adaptive tests, Rasch-based DIF statistics were highly correlated with generating DIF, but DIF statistics tended to be slightly smaller than in the three-parameter logistic model analyses. (SLD)

Hierarchical Bayes procedures for the two-parameter logistic item response model were compared for estimating item and ability parameters through two joint and two marginal Bayesian procedures. Marginal procedures yielded smaller root mean square differences for item and ability, but results for larger sample size and test length were similar.…

A method is presented for estimating the item characteristic curve (ICC) using polynomial regression splines. Estimation of spline ICCs is described by maximizing the marginal likelihood formed by integrating ability over a beta prior distribution. Simulation results compare this approach with the joint estimation of ability and item parameters.…

Using the constant information model, constant amounts of test information, and a finite interval of ability, simulated data were produced for 8 ability levels and 20 numbers of test items. Analyses suggest that it is desirable to consider modifying test information functions when they measure accuracy in ability estimation. (SLD)

Type I error rates of the likelihood ratio test for the detection of differential item functioning (DIF) were investigated using Monte Carlo simulations. The graded response model with five ordered categories was used to generate data sets of a 30-item test for samples of 300 and 1,000 simulated examinees. All DIF comparisons were simulated by…

By definition, differential item functioning (DIF) refers to unequal probabilities of a correct response to a test item by examinees from two groups when controlled for their ability differences. Simulation results are presented for an attempt to purify a test by separating out multidimensional items under the assumption that the intent of the…

The sensitivity of marginal maximum likelihood estimation of item and ability (theta) parameters was examined when prior ability distributions were not matched to underlying ability distributions. Thirty sets of 45-item test data were generated. Conditions affecting the accuracy of estimation are discussed. (SLD)

A model-based modification of the standardization index based on a multidimensional item response theory bias modeling approach is presented that detects and estimates differential item functioning (DIF) (item bias) simultaneously for several items as well as differential test functioning (DTF). This SIBTEST procedure is tested through a computer…

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…