Effects of automatic item eliminations based on item test analysis

Item test analysis is an aid to identify items that need to be eliminated from an assessment. An automatic elimination procedure based on item statistics, therefore, could help to increase the quality of a test in an objective manner. This was investigated by studying the effect of a standardized elimination procedure on the test results of a second-year course over a period of 6 successive years in 1,624 candidates. Cohort effects on the item elimination were examined by determining the number of additional items that had to be eliminated from three different tests in 3 successive academic years in two cohorts. The items that were part of more than one test and had to be eliminated according to the procedure in at least one of the tests appeared to have to be retained according to the same procedure in most of the other tests. The procedure harmed the high scoring students relatively more often than the other students, and the number of eliminated items appeared to be cohort dependent. As a consequence, automatic elimination procedures obscure the transparency of the grading process unacceptably and transform valid tests into inadequate samples of the course content.