The effectiveness of a behavior modification program combining cooperative learning with peer and self-evaluation was field tested with a group of 20 students in a 9th-grade class in beginning small engines. The students represented a mix of racial/cultural and economic backgrounds, were of average intelligence, and exhibited a variety of poor work habits and disruptive behavior. After an analysis of literature on disruptive behavior and its possible causes, a set of intervention strategies was formulated that included the following: a cooperative group learning program based on a set of project-developed illustrated engine parts assembly instruction sheets; instruction in self- and peer evaluation procedures and regular use of project-developed evaluation forms; and use of student-developed quizzes. The strategies were field tested for 6 weeks. Postintervention data confirmed a decrease in disruptive behaviors and poor work habits and an increase in student performance levels after the field test. (Appendixes constituting approximately one-third of this document include the following: tables summarizing initial data regarding students' work habits, disruptive behaviors, and performance; student sheets and illustrations dealing with engine parts assembly; sample peer and self-evaluation forms and data forms; sample student-generated quizzes; poststudy data; and illustrated study sheets. Contains 25 references.) (MN)