Ten item discrimination indices, across a variety of item analysis situations, were compared, based on the validities of tests constructed by using each of the indices to select 40 items from a 100-item pool. Item score data were generated by a computer program and included a simulation of guessing. (Author/CTM)

Teacher-selected test level resulted in: (1) most Educable Mentally Retarded students tested responding above chance levels on all subtests of the Metropolitan Achievement Test, (2) reliability coefficients comparable to those of the standardization sample, and (3) moderate to high positive point-biserial correlations for all subtest-level…