The Anchor Test Study (ATS) yielded equating tables for vocabulary, reading comprehension, and total reading scores for eight commonly used reading tests at the 4th, 5th, and 6th grade levels. Because of the original ATS sampling design which resulted in a nationally representative sample of school children at those grades, the equating tables might not be considered equally applicable for selected subgroups of the population--specifically, for black and Spanish-surnamed subgroups. The present study was done to determine whether use of the ATS equating tables for these two ethnic subgroups is warranted. Essentially, the analysis focused upon detecting interaction between test interrelationships and ethnic affilation in a way most relevant to the expected uses of the ATS equating tables--average differences between equivalent and obtained scores for each ethnic group, in various parts of the score range, were tested for significance. The detailed procedures for accomplishing the implied statistical tests are described. The analyses appear in Appendices A, B, and C (for grades, 4, 5, and 6, respectively) organized by vocabulary, reading comprehension, and total reading scores within grade level. The results did not indicate any systematic ethnic bias. The few isolated instances which did exist might be attributed largely to the sampling procedure used in the ATS; i.e., maximizing representation of the total population, rather than that of any specific subgroup. (RC)