Changing the order of items between alternate test forms to prevent copying and to enhance test security is a common practice in achievement testing. However, these changes in item order may affect item and test characteristics. Several procedures have been proposed for studying these item-order effects. The present study explores the use of…

This study used a diagnostic testing approach to compare the mathematics achievement of eighth-grade students across a sample of 20 countries, analyzing data from the Third International Math and Science Study-Revised (TIMSS-R, 1999). Using the rule-space method, student mastery was measured on 23 specific content knowledge and processing…