Scoring Classroom Achievement Tests: What To Do with the Hard Items?
This study compares the results of applying two commonly used methods of adjusting classroom tests when items are found to be too difficult: (I) dropping difficult items or (2) adding bonus points to the original score. Undergraduate teacher education students in a required measurement class were given the same five achievement tests during the fall (n = 54) and spring (n = 54) semesters. Four methods of adjusting students’ scores were applied: two methods dropped items from the test based on the difficulty value and rescored the tests, and two methods added a bonus percent to the unadjusted total score. Although correlations among semester percentage grades for the different methods were all above .97, only the addition of bonus points maintained the order of the students on the original test. The agreement among the methods in assigning letter grades (90 = A, etc.) varied from 13 to 93%. The effect of dropping items on the content validity and the reliability varied among the unit tests, depending on the characteristics of the items dropped.