What AEH explained regarding better accuracy away from the tail end is one important reason to take the SAT over its lesser siblings. Another reason is that you will be able to access better comparison stats since more students, including talent search kids, take the SAT. Still another reason is your DS will get practice with a test that will actually matter and that he will actually take for college admission. The PSAT 8/9 is basically a shorter version of the SAT with many of the hardest questions left out. You will get feedback on your DS' stamina and abilities with the hardest questions. When DS tried some SAT sections (unofficially) at ages 9-11, he didn't necessarily missed level 5 ( hardest) questions.
