This study compared the academic and social development of students who entered grade 1 very early (5:6 years or 5:7 years), in the mid range (5:8 to 6:3 years), and very late (6:4 years or older). The purpose of the study was to explore the hypothesis that the early grade 1 entrants would have continuing problems in both academic and social functioning relative to their older classmates. In order to assess the short and long term effects of school entrance age, a cross-sectional study was conducted. Approximately 200 students in grades 2, 6, 8, and 10, randomly selected from one school district in Alberta, Canada, participated in the study. Data on the subjects' academic and social adjustment were obtained from a combination of standardized tests, teacher ratings, and school records. Results provided only moderate support for the hypothesis. Although means and proportions for the different groups were found to fall quite consistently into the predicted pattern, few of the differences were statistically significant; enough variability was evident among students in each of the age groups to override differences between the groups. Results also indicated that young students were more at risk in terms of repeating a grade than older students, but that this was at least partially a result of lesser reluctance to hold a young student back. In terms of administrative decisions, results did not provide a clear statistical rationale for raising the entry age. (Author/MP)