The purpose of this study was to evaluate the utility of out-of-level testing (OLT) when it is applied to the assessment of special education students with mild learning handicaps. This evaluation of OLT involved testing hypotheses related to: (1) the adequacy of vertical scaling, (2) the reliability and (3) the validity of OLT scores. Fifty-eight special education students were tested. All students had measured reading achievement below the 20th percentile, and were integrated into the regular fifth or sixth grade classrooms for a portion of their academic programs. The appropriate in-level tests and two consecutively lower OLTs of the reading subtest of the California Achievement Test were administered approximately 10 days apart. The results suggest moderate support for the utility of OLT. It is suggested that the congruence between test content and the instructional programs may have considerably more influence over the reliability and validity of test data than would the use of OLT. (Author)