I found this WSJ article via Steve Sailer discussing the ineffectiveness of SAT preparation material, which is a highly lucrative industry. The following paragraph caught my eye:
The college counselors’ report concludes that, on average, prep courses yield only a modest benefit, “contrary to the claims made by many test-preparation providers.” It found that SAT coaching resulted in about 30 points in score improvement on the SAT, out of a possible 1600, and less than one point out of a possible 36 on the ACT, the other main college-entrance exam, says Derek Briggs, chairman of the research and methodology department at the University of Colorado in Boulder and author of the admissions counselors’ report.
The report was prepared by reviewing numerous academic studies from past years that examined the impact of test preparation on SAT scores. The studies predated the addition of the writing section of the SAT in 2005, which increased the possible score total to 2400 from 1600.
This confirms my long standing hunch that SAT scores can’t be improved that much. Though it is a admixture of testing crystalized and fluid intelligence, just about all students have the same basic ten years of education that is the platform of SAT material. Thus, the SAT tests more of a person’s natural “smarts” than people realize. The rest of the article is here.