Test-free person measurement with the Rasch simple logistic model

This research investigated the use of the Rasch simple logistic model in obtaining test-free ability estimates. Two tests each of word, picture, symbol, and number analogies were administered to college and high school students. Differences between scores on each pair of tests were analyzed to determine whether the ability estimates were independent of the tests employed. The results indicate that raw-score ability estimates are influenced by the difficulty of the items used in measurement but that Rasch ability estimates are relatively independent of the difficulty of these items. The need is discussed for additional research in which an individualized item-presentation procedure is used with the Rasch model