Modeling multidimensional test data with a unidimensional model can result in serious statistical errors, such as bias in item parameter estimates. Many methods exist for assessing the dimensionality of a test. The current study focused on DIMTEST. Using simulated data, the effects of sample size splitting for use with the ATFIND procedure for…

This study presents a procedure for detecting differential item functioning (DIF) for dichotomous and polytomous items in testlet-based tests, whereby DIF is taken into account by adding DIF parameters into the Rasch testlet model. Simulations were conducted to assess recovery of the DIF and other parameters. Two independent variables, test type…

Three studies explored the effects of grouping versus randomized items in questionnaires on internal consistency and test-retest reliability with samples of 80, 80, and 100, respectively, university students and undergraduates. The 2 correlational and 1 experimental studies were reasonably consistent in demonstrating that neither format was…

In two studies, selections of evaluation form items were negatively worded and presented before or after overall student ratings. Ratings of courses and instructors were not significantly affected by wording. Differences in the global assessment of the courses are discussed. (Author/CM)