The group's report last month on standardized tests said most prep programs result in a 20- to 30-point gain.
Larger increases could be due to such factors as familiarity with the test, more time in school or simple maturity, said Derek Briggs, a test expert at the University of Colorado.
Some consultants assert that greater gains can be attained through tutoring or prep courses.
Big education firms, such as Kaplan and Princeton Review, guarantee improvements if students complete the program.
Alex Weiner of CollegeWise in White Plains, N.Y., gets specific, boasting 110-point gains in math and 60 points in reading and writing. His tutoring fee: $250 an hour. "The single best thing a kid can do is take a practice SAT and analyze the results with a tutor," he said.
Briggs said prep can help students at the high end and in need of a small bump to attract highly competitive schools.
- Susan Snyder
Q&A With College Counselor
Ask questions of admission deans at Ursinus College and the University of Delaware, noon to 1 p.m. Monday:
Also online, college entry tips and bios of students in this series.
Contact staff writer Susan Snyder at 215-854-4693 or ssnyder@phillynews.com