In this study, data were collected from 163 Instruction and Research (I&R) Units from 45 elementary multiunit schools (MUS) in 12 different states to determine the relationships between I&R unit effectiveness and unit member compatibility, unit leader's behavior, and the level of task structure as perceived by the unit members. The instrument developed and used for the survey consisted of questionnaires to be completed by unit members on their background, their unit leader's behavior, the operation of their I&R unit, and their perception of task structure and of themselves. The major conclusions of the study were that: (a) only leader behavior significantly influenced I&R unit effectiveness; (b) there is no significant relationship between I&R unit effectiveness and the number of unit members; and (c) there is no significant relationship between unit effectiveness and the number of hours per week which the unit meets. Several factors limit the study: (a) the consideration of only intragroup variables, (b) the varability of the selection process, (c) the sample selection process, and (d) the assumption that data collected reflect truthfulness in the subjects' responses. (Author/HMD)