A study was conducted utilizing new postsecondary Interstate Distributive Education Curriculum Consortium (IDECC) curriculum materials to evaluate through experimental research the effectiveness of IDECC's systematic teaching approach. The study was quasi-experiential involving two levels of treatment: (1) the postsecondary IDECC teaching approach and (2) the postsecondary traditional teaching approach. Sixteen classes were randomly selected from a population of twenty-eight volunteer sites. The IDECC approach utilized selected postsecondary IDECC competency-based materials as their unit of instruction. The traditional instructors developed lesson plans as their instructional material within a workshop setting. Findings based on analysis of covariance by regression utilizing forty sources of variance indicated that only one source of variance, the effect of schools, made a significant contribution. In addition, it was found that teaching approach when in combination with related work experience made a significant contribution to the student's posttest score. (Appended material includes a unit of instruction outline, objectives and resources utilized in the study, pretest and posttest questionnaires, and the IDECC instructor's handbook.) (LRA)