This document reports on the procedures and results of the Atlanta Public Schools (APS) testing program in changing from the Iowa Tests of Basic Skills (ITBS), administered to grades 1 through 7 from 1973-79, to the California Achievement Tests (CAT), Form C, administered in Spring 1980 to provide a continuous testing program from the elementary through secondary grades. The ITBS, CAT, Metropolitan Achievement Tests (MAT), and SRA Achievement Series were reviewed and evaluated on 18 criteria, the foremost being compatibility with the APS curriculum. The CAT was selected. An equating study using the method of equi-percentile equating of scores was utilized to determine the relationship of scores between the 1971 edition of ITBS and the 1978 edition of CAT. It was found that correlations for the two tests were higher for the on-level cells, and that the correlations for Mathematics were higher than those for Reading Comprehension. In 1980 the CAT test battery and the ITBS Reading Comprehension subtest were administered. Score conversions produced equivalent results only for the second grade. The first grade CAT scores were equivalent to the national norm; other grades scored below the national norm. Reading Vocabulary scores were particularly low. The highest scores occurred in Spelling. (PN)