There were no significant differences among the students of the three treatment groups selected from 21 fifth grade classrooms. The treatment groups included students who read at one of five levels as determined by an individual informal reading inventory, students who read at one of five levels as determined by a group informal reading inventory and, students who read at only the middle (C) level of the five levels supplied by the publishers. The results of the statistical analysis indicated that the informal reading inventory will place students 1.3 years lower in the materials used in this study than would the Metropolitan Reading Achievement Test. The materials were written at five levels of reading difficulty to better meet the reading ability spread found in the intermediate grades. The significance of student placement on achievement gain was evaluated by an analysis of variance. Groups were also equated with respect to reading level and teacher rating by an analysis of covariance. (EB)