He teaches graduate students in the master's and doctoral counselor education program with a focus on school counseling. Dr. Mullen is a National Certified Counselor, a National Certified School Counselor, and an Approved Clinical Supervisor. He presents at state, regional and national conferences in the fields of counseling and education along with publishing articles in scholarly journals. Furthermore, he is on the editorial board for the journals Counseling Outcome Research and Evaluation, Measurement and Evaluation in Counseling and Development, and Counseling and Values. Dr. Mullen's general research areas include school counseling, counselor education and supervision, and counseling children and adolescents.