This study was conducted in an elementary school where the Wisconsin Design for Reading Skill Development had been implemented and developed for several years. Its aim was to determine what happened to individual children during reading instruction when the Design was being systematically used. A case history approach was used, and the school was organized into units in which two grade levels were usually combined. The study was limited to students in grades two through six. Within each unit one child was randomly selected from a high IQ group, one from an average IQ group, and one from a low IQ group. The IQ scores were obtained from the school records and were the subjects' most recent scores on the Lorge-Thorndike Intelligence Test. Clerical aides were trained to observe the subjects during skill instruction in reading whenever it was taking place. The aides made one observation a day for ten weeks. Results from the study indicated that individualization of reading instruction was apparent. Also found were anticipated differences among age groups and the individualizing of reading instruction in elementary skills for students of low and average ability. (WR)