This study analyzed the impact of the Developmental Discipline Management System (DD) on teaching effectiveness and student achievement in special needs classrooms. DD was developed as a human centered, systems approach to education. Its core philosophy was to help each child achieve self mastery and mastery of subjects and to help teachers feel the importance and dignity of working with children. The population for the study consisted of all certified Chapter One teachers and their assigned students in the primary grades of an inner city Arizona school district. Teachers received 15 hours of training in DD. The teachers in this inner-city district who chose to use the program in their second and third grade classes during the school year were the experimental group. The control group consisted of teachers who chose not to use the program. Student learning was assessed using the California Achievement Test as a pretest and a post-test administered to the children in each of the 31 classrooms. Academic achievement in the classrooms using DD significantly increased over that of the control group. Results of a teacher confidence survey showed expression of confidence and satisfaction with DD and a belief that the program had significantly improved their teaching. At the end of the year the district administrator rated each of the teachers with a competency evaluation tool. The 18 DD teachers received significantly higher ratings in 5 areas. The teacher assessment tool is appended. (Contains 17 references.) (JB)