Although research in goal setting has demonstrated that specific, difficult goals lead to better performance, more refined research on the affect of participative decision making and supportive leadership on goal setting has produced ambiguous results. To investigate the relative importance of goal setting, leader supportiveness, and task structure on performance in a clerical task, 40 male college students were assigned to one of eight conditions in indexing a chapter from a textbook. The assigned conditions were: assigned vs. participatively set goals; supportive vs. nonsupportive leader; and structured vs. unstructured task. Goal difficulty remained constant. Upon completion of the task, subjects evaluated goal setting and leadership style on a Likert-type questionnaire and the Consideration Scale of the Leader Behavior Description Questionnaire Form 12. An analysis of the results showed that increasing task structure significantly enhanced performance as did assigned task goals. Supportiveness interacted with method of goal setting such that a supportive leader who assigned a performance goal produced significantly higher worker performance levels than any other condition. (BL)