This study sought to test the predictive power of the hypothesis that in formal organizations, groups of complementary (different) psychological types will perform two types of tasks more efficiently and effectively than groups consisting of compatible psychological types. The Myers/Briggs Type Indicator (MBTI) of Jungian personality types was distributed to the superintendent and principals in 25 randomly selected school districts in a southwestern state in order to determine compatible and complementary personality types, and 10 compatible and 10 complementary management teams were identified from this group to participate in the next phase of the study. The structured and ambiguous tasks for the study were designed according to Fiedler's (1967, 1971) contingency model. The researcher visited each school site to administer the structured and ambigous tasks and to record the time used by each team to complete the tasks. Results were submitted to a panel of judges to establish a numerical score of performance. The structured task for the study was the completion of two bus routes, while the ambiguous task was to consider a case study, reach consensus on the team's position, and defend that position in a paper. The study confirms findings of both small-group and contingency theorists that the type of task and interpersonal relations are variables affecting task team performance. However, it appears that psychological type of task team members is a more significant factor when performing an ambiguous task than in performing a structured task. A bibliography is included, and statistical correlations for each group are appended. (TE)