The reliability and validity of a tailored testing procedure based on the simple logistic model was determined for an achievement test in statistics and measurement. The test was administered on a CRT terminal to students from graduate and undergraduate measurement courses. Equivalent form reliability over a one-week interval was found to be 0.595…

This paper explores the effects of item choice on ability estimation when using a tailored testing procedure based on the Rasch simple logistic model. Most studies of the simple logistic model imply that ability estimates are totally independent of the items used, regardless of the testing procedure. This paper shows that the ability estimate is…

This primer is an introduction to item response theory (also called item characteristic curve theory, or latent trait theory) as it is used most commonly--for scoring multiple choice achievement or aptitude tests. Written for the testing practitioner with minimum training in statistics and psychometrics, it presents and illustrates the basic…