This study was designed to compare the utilization of instructional time of first grade classroom teachers with and without full-time teacher aides, to compare the academic performance of children in these two groups, and to examine the relationship between teacher and aide activity. A sub-purpose was the development of an observation instrument to provide a timed record of teacher behavior, and this was found to be valid and reliable. Five research questions were formulated and statistical hypotheses established to answer them. Ten teachers with aides and ten without were studied by trained observers for four 10-minute periods. Pupil achievement was measured by the Lee-Clark Reading Readiness Test at the end. No significant difference was found between the two groups of teachers in clerical activities, routine activities, total group instruction or differentiated instruction. The teachers with aides spent more time in clerical activities and total group instruction. There was no common pattern of aide activity and teacher activity. There was no evidence that the aides provided more instructional time leading to improved pupil performance, although it seemed that teachers with aides were somewhat more successful in improving the achievement of lower level pupils. (Author/MBM)