Karcher has researched and written about the contexts and individual characteristics that help mentors to persist, what happens when mentoring relationships end prematurely, and what occurs between mentors and mentees in successful matches. He has focused primarily on cross-age mentoring in schools, and has developed and evaluated school-based mentoring programs in Texas, Wisconsin, and New York. He is on the editorial boards of Psychology in the Schools and Professional School Counseling. He has just completed a three-year study of mentoring funded by the U.S. Department of Education and is currently examining school-based mentoring conducted through Communities In Schools.