 His research includes the advancement of the concepts of "the Achievement Gap," "Affirmative development of academic ability," and "Supplementary Education," all which focus on improving the quality of academic achievement in diverse learners.His publications consist of more than 175 articles and 15 books and monographs.His current research study "Correlates of High Achievement" is investigating, through several projects, personal, ecological, and institutional factors that are associated with high levels of academic achievement in a variety of ethnic minority students.