This paper reports on the work of Ransom A. Mackie, a scholar and instructor in Massachusetts under the mentorship of G. Stanley Hall, the prominent adolescent psychologist. Mackie published a book in 1920 which, along with further writings, outlines a cooperative learning strategy. Performance-based education and authentic assessment proponents could benefit from the use of Mackie's work. Mackie divides the strategy into the six roles of leader, critic, chairperson, class, teacher, and secretary. The paper outlines the role expectations for each of these members and describes the benefits to be gained from the shared learning experience of the group. The strategy is designed to encourage active participation, stimulate initiative and originality, correct misinformation, develop the ability to communicate, expand experiences, build knowledge, and offer students the opportunity to think, reason, judge, and make decisions. (EH)