Item mappings are widely used in educational assessment for applications such as test administration (through test form assembly and computer assisted testing) and for criterion-referenced (CR) interpretation of test scores or scale anchoring. Item mappings are also used to construct ordered item booklets in the CTB/McGraw Hill Bookmark standard…

By noting that a Rasch or two parameter logistic (2PL) item belongs to the exponential family of random variables and that the probability density function (pdf) of the correct response (X=1) and the incorrect response (X=0) are symmetric with respect to the vertical line at the item location, it is shown that the conjugate prior for ability is…

Latent trait theory supposes that, in testing situations, examinee performance on a test can be predicted (or explained) by defining examinee characteristics, referred to as traits, estimating scores for examinees on these traits and using the scores to predict or explain test performance (Lord and Novick, 1968). In view of the breakthroughs in…