To Scale or not to Scale: Insights from a Study of Grade Comparability in CXC Examinations
- Academic Achievement,
- Grade Comparability,
This study sought to ascertain the extent to which the use of statistical scaling procedures to establish comparable Grade III/IV cut scores for different examinations of the same subject resulted in cut scores that were comparable to those obtained when judgmental procedures are used. The study used data from three subjects of the Caribbean Examinations Council (CXC) where the same Grade III/IV cut scores were retained over a five-year period. Through linear transformation, the Grade III/IV cut scores for each subject were converted to scale scores on a base form. The extent to which scaling procedures validated CXC’s maintenance of the same Grade III/IV cut scores across years was considered. For all but one of the 11 cut scores considered in this study, the calculated scale scores were dissimilar from those retained by CXC. The calculated scale scores, therefore, could not be regarded as comparable to the cut scores established by CXC through the use of its judgmental procedures. However, it was found that the direction of change in the proportion candidates obtaining Grades I to III with the CXC judgmental procedures was consistent with the outcome of scaling.