To reduce the impact of parameter estimation errors on IRT linking results, recent work introduced two information-weighted characteristic curve methods for dichotomous items. These two methods showed outstanding performance in both simulation and pseudo-form pseudo-group analysis. The current study expands upon the concept of information…

We used simulation techniques to assess the item-level and familywise Type I error control and power of an IRT item-fit statistic, the "S-X"[superscript 2]. Previous research indicated that the "S-X"[superscript 2] has good Type I error control and decent power, but no previous research examined familywise Type I error control.…

The purpose of this study is to address the necessity of subscore equating and to evaluate the performance of various equating methods for subtests. Assuming the random groups design and number-correct scoring, this paper analyzed real data and simulated data with four study factors including test dimensionality, subtest length, form difference in…

Karabatsos compared the power of 36 person-fit statistics using receiver operating characteristics curves and found the "H[superscript T]" statistic to be the most powerful in identifying aberrant examinees. He found three statistics, "C", "MCI", and "U3", to be the next most powerful. These four statistics,…

Empirical information regarding performance of model-fit procedures has been a persistent need in measurement practice. Statistical procedures for evaluating item fit were applied to real test examples that consist of both dichotomously and polytomously scored items. The item fit statistics used in this study included the PARSCALE's G[squared],…

Tests of model misfit are often performed to validate the use of a particular model in item response theory. Douglas and Cohen (2001) introduced a general nonparametric approach for detecting misfit under the two-parameter logistic model. However, the statistical properties of their approach, and empirical comparisons to other methods, have not…

Type I error rates and rejection rates for three-dimensionality assessment procedures were studied with data sets simulated to reflect short tests and small samples. Results show that the G-squared difference test (D. Bock, R. Gibbons, and E. Muraki, 1988) suffered from a severely inflated Type I error rate at all conditions simulated. (SLD)

Adaptive tests offer the advantages of reduced test length and increased accuracy in ability estimation. However, adaptive tests require large pools of precalibrated items. This study looks at the development of an item pool for 1 type of adaptive administration: the computer-adaptive sequential test. An important issue is the sample size required…

Empirical reliabilities of scores based on item-pattern scoring, using 3-parameter item-response theory and number-correct scoring, were compared within each of 5 score metrics for at least 900 elementary school students for 5 content areas. Average increases in reliability were produced by item-pattern scoring. (SLD)

The impact of capitalizing on chance in item selection on the accuracy of test information functions was studied through simulation, focusing on examinee sample size in item calibration and the ratio of item bank size to test length. (SLD)

In low-stakes testing, the motivation levels of examinees are often a matter of concern to test givers because a lack of examinee effort represents a direct threat to the validity of the test data. This study investigated the use of response time to assess the amount of examinee effort received by individual test items. In 2 studies, it was found…

Effects of altering test difficulty on examinee ability measures and test length in a computer adaptive test were studied for 225 medical technology students in 3 test difficulty conditions. Results suggest that, with an item pool of sufficient depth and breadth, acceptable targeting to test difficulty is possible. (SLD)