Applications of polytomous IRT models in applied fields (e.g., health, education, psychology) are abound. However, little is known about the impact of the number of categories and sample size requirements for precise parameter recovery. In a simulation study, we investigated the impact of the number of response categories and required sample size…

Fully "qualitative" surveys, which prioritise qualitative research values, and harness the rich potential of qualitative data, have much to offer qualitative researchers, especially given online delivery options. Yet the method remains underutilised, and there is little in the way of methodological discussion of qualitative surveys.…

When using the Rasch model, equating with a nonequivalent groups anchor test design is commonly achieved by adjustment of new form item difficulty using an additive equating constant. Using simulated 5-year data, this report compares 4 approaches to calculating the equating constants and the subsequent impact on equating results. The 4 approaches…

This study investigates the effects of sample size and test length on item-parameter estimation in test development utilizing three unidimensional dichotomous models of item response theory (IRT). For this purpose, a real language test comprised of 50 items was administered to 6,288 students. Data from this test was used to obtain data sets of…

An automated item selection procedure in Mokken scale analysis partitions a set of items into one or more Mokken scales, if the data allow. Two algorithms are available that pursue the same goal of selecting Mokken scales of maximum length: Mokken's original automated item selection procedure (AISP) and a genetic algorithm (GA). Minimum…

Examined the effects of test length and sample size on the alternate forms reliability and equating of simulated mathematics tests composed of constructed response items scaled using the two-parameter partial credit model. Results suggest that, to obtain acceptable reliabilities and accurate equated scores, tests should have at least 8 6-point…

The power of the procedure of W. Stout to detect deviations from essential unidimensionality in two-dimensional data was investigated for minor, moderate, and large deviations from unidimensionality using criteria for deviations from unidimensionality based on prior research. Test lengths of 20 and 40 items and sample sizes of 700 and 1,500 were…

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)

The results obtained from two basic types of pre-equatings of tests were compared: the item response theory (IRT) pre-equating and section pre-equating (SPE). The simulated data were generated from a modified three-parameter logistic model with a constant guessing parameter. Responses of two replication samples of 3000 examinees on two 72-item…

Because latent trait models require that large numbers of items be calibrated or that testing of the same large group be repeated, item parameter estimates are often obtained by administering separate tests to different groups and "linking" the results to construct an adequate item pool. Four issues were studied, based upon the analysis…

Factor structure of the Reactions to Tests (RTT) scale measuring test anxiety was studied by testing a series of confirmatory factor models including a second-order structure with 636 college students. Results support a shorter 20-item RTT but also raise questions about the cross-validation of covariance models. (SLD)

When criterion-referenced tests are used to assign examinees to states reflecting their performance level on a test, the better known methods for determining test length, which consider relationships among domain scores and errors of measurement, have their limitations. The purpose of this paper is to present a computer system named TESTLEN, which…

Two aspects of criterion referenced testing are discussed: cutting scores and test length. Several practices in determining passing scores are enumerated: (1) setting passing scores so that a predetermined percent of students pass; (2) inspecting each test item to determine how important it is that it be answered correctly; (3) determining the…