Can TIMMS mathematics assessments be implemented as computerized adaptive test?

In recent years, there has been a growing interest and extensive use of computerized adaptive testing (CAT) especially in large-scale assessments. Numerous simulation studies have been conducted on both real and simulated data sets to determine the optimum conditions and develop CAT versions. Being one of the most popular large-scale assessment programs, Trends in International Mathematics and Science Study (TIMSS) has been implemented as paper and pencil tests to monitor student achievement in mathematics and science at fourth and eighth grade levels since 1995. The purpose of this study is to investigate the optimum CAT algorithm for TIMSS eighth grade mathematics assessments. Since Turkey and USA participated in 2007, 2011 and 2015 administrations, their data were combined and then 393 items were calibrated on the same scale by using marginal maximum likelihood estimation method. With this item pool, several scenarios were proposed and tested to determine not only the optimum starting rule, ability estimation method, test termination rule but also the efficiency of exposure control method. The results of the study indicated that estimating abilities with expected a posteriori method after 6 random items, terminating the fixed-length test after 20 items seemed to be the optimum algorithm for TIMSS eighth grade mathematics assessments. Also, it was found that using item exposure control had a prior importance for the effective use of the item pool. This study has some implications for both national and international large-scale test developers in determining the optimum CAT algorithm and its consequences compared with paper and pencil versions.