Indices for Detecting Unusual Patterns: Links Between Two General Approaches and Potential Applications

Abstract

Two distinct approaches, one based on item re sponse theory and the other based on observed item responses and standard summary statistics, have been proposed to identify unusual response patterns of re sponses to test items. A link between these two ap proaches is provided by showing certain correspon dences between Sato's S-P curve theory and item response theory. This link makes possible several ex tensions of Sato's caution index that take advantage of the results of item response theory. Several such in dices are introduced and their use illustrated by appli cation to a set of achievement test data. Two of the newly introduced extended indices were found to be very effective for purposes of identifying persons who consistently use an erroneous rule in attempting to solve signed-number arithmetic problems. The poten tial importance of this result is briefly discussed.