<P> The SAT is typically taken by high school juniors and seniors . The College Board states that the SAT measures literacy and writing skills that are needed for academic success in college . They state that the SAT assesses how well the test takers analyze and solve problems--skills they learned in school that they will need in college . However, the test is administered under a tight time limit (speeded) to help produce a range of scores . </P> <P> The College Board also states that use of the SAT in combination with high school grade point average (GPA) provides a better indicator of success in college than high school grades alone, as measured by college freshman GPA . Various studies conducted over the lifetime of the SAT show a statistically significant increase in correlation of high school grades and college freshman grades when the SAT is factored in . A large independent validity study on the SAT's ability to predict college freshman GPA was performed by the University of California . The results of this study found how well various predictor variables could explain the variance in college freshman GPA . It found that independently high school GPA could explain 15.4% of the variance in college freshman GPA, SAT I (the SAT Math and Verbal sections) could explain 13.3% of the variance in college freshman GPA, and SAT II (also known as the SAT subject tests; in the UC's case specifically Writing, Mathematics IC or IIC, plus a third subject test of the student's choice) could explain 16% of the variance in college freshman GPA . When high school GPA and the SAT I were combined, they explained 20.8% of the variance in college freshman GPA . When high school GPA and the SAT II were combined, they explained 22.2% of the variance in college freshman GPA . When SAT I was added to the combination of high school GPA and SAT II, it added a . 1 percentage point increase in explaining the variance in college freshman GPA for a total of 22.3% . </P> <P> There are substantial differences in funding, curricula, grading, and difficulty among U.S. secondary schools due to U.S. federalism, local control, and the prevalence of private, distance, and home schooled students . SAT (and ACT) scores are intended to supplement the secondary school record and help admission officers put local data--such as course work, grades, and class rank--in a national perspective . However, independent research has shown that high school GPA is better than the SAT at predicting college grades regardless of high school type or quality . </P> <P> Historically, the SAT was more widely used by students living in coastal states and the ACT was more widely used by students in the Midwest and South; in recent years, however, an increasing number of students on the East and West coasts have been taking the ACT . Since 2007, all four - year colleges and universities in the United States that require a test as part of an application for admission will accept either the SAT or ACT, and over 950 colleges and universities do not require any standardized test scores at all for admission . </P>

What is the purpose of the act and sat