Since the inception of the Educational Voucher Demonstration in Alum Rock School District, San Jose, California, standardized achievement tests have been a major component of its evaluation. However, the results of the tests have been difficult to interpret. This paper explores the effects of using different levels of the Metropolitan Achievement Test (MAT) within the same grade. The standard score scale does not permit a student's score on one level of the MAT to be generalized to other levels, even adjacent levels. This suggests that the level of the MAT used in Alum Rock did affect evaluation results. The study shows that had the Alum Rock fifth graders been given the Intermediate level MAT (the level standardized for 5th grade) their mean score would probably have been higher. The study also shows that the type of test administrator (regular teacher, substitute teacher, other teacher) seems to have had little effect on the students' scores, hence did not affect the evaluation results. 18 pp. Ref.