48 states. There has also been a positive correlation between providing merit-based aid and degree completion. As the level to qualify for state need-based aid is lowered, the probability of persistence increases. Low-income families now must pay more to attend college, making it harder for them to attain higher education. In 1980, low-income families used 13% of their income to pay for one year of college. In 2000, this proportion grew to 25 percent of their income, while high-income families used less than 5% of their income. Fully understanding how need and merit (non-need) aid is determined is critical to ensure greater access to higher education. It is clear that at both private and public colleges and universities family income has a major impact on need-based financial aid. As colleges and universities compete for students, the demarcation between merit-based aid and need-based aid is less clear. While there has been a traditional distinction between need-based and merit-based funding, recent trends indicate that these two categories are more blurred than their labels would suggest. Research confirms that merit-based financial aid often takes into account student need and vice versa. Controversy has also risen regarding performance-based funding. Performance-based funding is a system in which the state's higher education budget is allocated to institutions by several measures to best determine allocation of funds. This system has been criticized due to the complexity of the measurements as well as the resulting changed environment and goals of campuses. Many have criticized performance-funding, noting an overemphasis of test scores without consideration of other possible measures. A 2006 report by Michael S. McPherson and Morton Owen Schapiro indicated that financial aid to students in the 1990s held the strongest correlation with student SAT scores. The report was conducted in the interest of looking directly at the relationship between financial aid grants and various factors, with specific focus on the variables of family income level and SAT scores and minor focus on personal variables, such as race and gender. The reason these factors were given greater consideration was that, according to McPherson and Schapiro, the information was readily available and led to a more meaningful comparison across students than variables like high school GPA. The report also made clear that it ignored the distinctions that universities make between "need-based" and "merit-based" aid. McPherson and Schapiro argued, "Although it is commonplace to track the importance of merit as opposed