Judith A Spray

• Effects of item difficulty heterogeneity on the estimation of true-score and classification consistency (ACT research report series)
• Identifying nonuniform DIF in polytomously scored test items
• Multiple-category classification using a sequential probability ratio test
• Performance of the Mantel-Haenszel statistic and the standardized difference in proportions correct when population ability distributions are incongruent
• Performance of three conditional DIF Statistics in detecting differential item functioning on simulated tests
• The effect of item parameter estimation error on decisions made using the sequential probability ratio test