A study was conducted to determine whether primary school children who were taught reading with an experimental modality prescriptive-diagnostic reading program achieved higher reading comprehension scores in the intermediate grades than did children who were taught reading with a traditional reading approach. The experimental group was composed of 369 children, while the traditional group consisted of 385 children. T-tests were used to locate significant differences between the children's third and fifth grade mean equivalent scores and their third through fifth grade mean gain scores on the reading comprehension section of a standardized reading test. The Cognitive Abilities Tests nonverbal aptitude scores were also compared by T-tests. Both the traditional and the experimental reading approaches were found to produce similar results in reading comprehension. (Author/FL)