In high school settings the behavior of students can have significant impacts on educational outcomes. This study tests Bronfrenbrenner's ecological systems theory by quantitatively studying academic and discipline measures of 9th grade students before and after teachers participated in the Time To Teach (TTT) professional development training. Data was analyzed using general linear models to determine if different students were affected differently when teachers made changes in their classrooms based on the TTT training. The student subgroups considered were those of different ethnicities, those of different socioeconomic status, and those receiving special education services. While the outcomes indicated that the training did affect each of the subgroups' academics and discipline, the effect did not follow the expected outcomes. Recommendations for future research of classroom management trainings for high school teachers, and of the TTT training are made based on the results of the study. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]