A Los Angeles bilingual elementary school was evaluated for the effectiveness of its dual reading program for bilingual first graders, the effectiveness of the native language literacy approach for Spanish dominants, and evidence of bias in the Comprehensive Tests of Basic Skills (CTBS). One hundred thirty-one Spanish and English dominant children were assessed with the CTBS in grades 3, 4, 5, and 6 for achievement in English reading during 1975-78. Spanish dominants were divided according to the grade level at which they began a dual reading program: grade 1 (SD-I), grade 2 (SD-II) and grade 3 (SD-III). English dominants (ED) were grouped by ethnicity: Hispanics, Blacks, Native Americans, Asians, and Anglos. The results indicated no apparent advantage or disadvantage for bilingual first grade dual readers. The findings also demonstrated the effectiveness of the native language literacy approach, in that the Spanish dominants in three to four years matched the reading level attained by English dominants in six to seven years. Chi square analyses of each subgroup's CTBS raw scores in relation to the median scores indicated no apparent test bias. (Author)