programs are aimed at students whose parents earn less than a certain income — the figures vary by college or university. These new initiatives were designed to attract more students and applicants from lower socioeconomic backgrounds, reduce student debt loads, and provide the offering institutions with an advantage over their rivals in attracting commitments from accepted students. Most students prefer no-loan financial aid as a way to relieve the amount of debt they are in after college The following colleges and universities offer such no-loan financial aid packages as of March 2008: Loan cap Some universities have opted to have a "loan cap" program, which is a maximum loan — either per year or for the four years combined — designed to reduce the cost of attendance for low-income and middle-class students. The following schools have a loan cap program: Effect of financial aid on enrollment, persistence, and degree attainment Studies examining the effects of financial aid on postsecondary outcomes have generally found positive effects. For instance, a study reviewing the literature on the effects of grant aid on enrollment finds that grant aid positively increases college enrollment, with approximately 3 to 4 percentage points increase in the likelihood of enrollment for a $1,000 reduction in costs. Similarly, a systematic review and meta-analysis by Tuan Nguyen and colleagues examining the effects of grant aid find that, across more than 40 studies, grant aid increases the probability of students persisting from year to year and of completing their degree by 2 to 3 percentage points, and an additional $1,000 of grant aid improves year-to-year persistence and degree attainment by 1.5 to 2 percentage points. This comprehensive study also finds that grant aid programs with additional non-monetary supports such as academic support and advising have larger effects, and that grant aid effects are weaker for merit-based aid than for need-based aid. In a study on the correlation between the price of higher education and enrollment rates, Donald Heller finds that the amount of financial aid available for students is a strong factor in enrollment rates. Different factors have different effects on financial aid: Decreases in the amount of financial aid leads to decreases in enrollment. However, different types of financial aid have differing effects. Grant awards tend to have a stronger effect on enrollment rates. Changes in tuition and financial aid affect poorer students more than they affect students with higher incomes.