SAT is used as a prerequisite for admission into college or under graduation in US for any program. The SAT I is a three-hour test that measures verbal and mathematical reasoning skills students have developed over time and skills they need to be successful academically. Many colleges and universities use the SAT as one indicator among others - class rank, high school GPA, extracurricular activities, personal essay, and teacher recommendations - of a student's readiness to do college-level work. The test is administered several times a year.