For example, several experiments suggest that smaller schools and smaller classes may help disadvantaged students (although the benefits of such programs for the general student population remain controversial). Supplemental education, including afterschool and mentoring programs such as Big Brothers Big Sisters, have been shown to boost school attendance (Grossman and Tierney, 1998).
Increasing school time – either through longer school hours or summer school – also has found some support (Jacob and Lefgren, 2004). Higher education In many ways, higher education represents the strongest part of the U.S. educational system, as demonstrated by the fact that students from all parts of the world come here to  BIS Review 106/2007  5  study.