Data from four of the Cooperative First Grade Studies (1964-1965) were reanalyzed for four first grade projects, (Fry, Hayes, Mazurkiewicz, and Tanyzer). These projects were selected because they compared the Initial Teaching Alphabet approach with traditional orthography-basal reader approaches. The focal point of this reanalysis was to study the effect of the treatment on the development of the grapho-phonemic and semantic subsystems underlying comprehension. A total of 565 subjects in 37 classes were in the ITA group and 533 subjects in 36 classes were in the basal treatment group. The data which was reanalyzed consisted of three instructional measures collected in the first month of school, four selected subtests from the Stanford Achievement Test collected after 140 days of instruction in the first grade; and three selected subtests from the Stanford Achievement Test collected at the end of second grade. Six of the eight comparisons of grapho-phonemic development revealed a significant difference in favor of ITA. Differences in underlying systems, not tested for in the First Grade Studies, apparently are not realized in reading comprehension at the end of the first grade. (MKM)