Academic researchers have repeatedly tried to determine whether coaching improves SAT scores. It is a difficult question to answer objectively because of the confounding variables.
Highly motivated students—like those who sign up for test-prep courses—are likely to improve no matter what. Just taking the test again often raises scores. And it is hard to distinguish the effects of test prep from other factors that may contribute to a better score.
Still, different studies over the years have suggested coaching tends to improve performance, though perhaps less dramatically than some test-prep companies suggest as researchers have found some improvement was likely to occur without coaching.
“The mythology is that students who are scoring in the 500s will get into the 750 range,” said Derek Briggs, a professor at the University of Colorado School of Education who has studied the effects of test preparation. “A realistic bump from commercial test prep might be about 20 to 30 points on math and verbal sections combined, but that’s on top of whatever baseline increase we’d expect of students who do everything except get commercial test prep.”