A study to explore the effectiveness of the Columbus, Ohio, Public School Systems' compensatory education program on the reading and mathematics achievement of pupils in fourth, fifth, and sixth grades was conducted. Intent of the study was (1) To study the differential achievement reached by all eligible pupils; and (2) To analyze a selected number of control variables. A modified version of the effect parameter analysis developed by Coleman was used. Data were derived from the records held by the school system on fourth, fifth and sixth grade pupils. Data were organized by: (1) listing all pupils in these three grades enrolled in the program, (2) determining those pupils underachieving at least one year below grade level, (3) determining those underachievers who possess a measured intelligence 80 and who were enrolled in summer school, (4) classifying all pupils identified as meeting or not meeting the achievement criterion, and (5) classifying all pupils who attended. An analysis of the reading achievement grade scores and an analysis of the mathematics computational grade equivalency scores were performed. Results include: (1) The supportive services had no statistically significant impact on the reading achievement of pupils; (2) Among low intelligence enrollees, the mathematics program component was associated with a diminishing effect on participating pupils' reading achievement; and (3) Pupils who participated in the reading program components improved their reading achievement. (CK)