The SAT is taken only by students applying to college, who are on average smarter than high school juniors and seniors in general.... I saw a study once showing that the average SAT score on an unselected sample of high school seniors was considerably lower (maybe 100 points for math + verbal) than the average of students who sign up to take the test.
You'll have to show me that study before I can comment on it. How old is it? How many students were in the sample? Did they only test students who did NOT sign up for the SAT as part of the unselected sample? Etc.
Interesting: because of the national mania to send everyone to college, more students are taking the SAT. Yet they don't seem to be doing terribly well. For example,
according to the College Board, only 43% of 1.65 million seniors who took the SAT in 2011 got scores of 1550 or higher, which it considers to be the minimum score for success in college. (
Note: I find the upbeat perkiness of that depressing press release to be rather odd.)
The
US Dep't of Education says that there were 14.5 million public high school students in 2011, and an estimated 1.36 million more in private schools. This is just under 4 million high school seniors.
So 41% of high school seniors took the SAT in 2011. Measuring very crudely, this number would include students with IQs all the way down to 103-104 (Notes: I'm not claiming everyone with an IQ>104 took the test or that no one with an IQ <103 took it. I also reckon that some of the best students took it as 10th or 11th graders, got super-high scores the first time, and didn't take it again).
Interestingly enough, by using my crude estimation system, roughly 60% of SAT takers would have had IQs of at least 115, which is the IQ benchmark for being able to succeed in college. This number fits nicely with performance on the test (only 43% of test takers got the College Board's college-success score). So I'm reconsidering my idea that the test isn't a good rough proxy for IQ.
But big disclaimer: there could be other factors at work, and of course my estimates are very crude and I could be way off here. For example, the SAT tests your knowledge of information and you can study to improve your score. At least a portion of scores probably reflect course content and study habits.
So, yes, many of the SAT takers are smarter and the average IQ is almost certainly higher. But most of them are probably in the average range of ability.
And I stand by what I said about the ceiling of the test. The score distribution at the top of the math test is
quite weird:. 1,250 students scored 790, yet eleven times that number (~13,800) scored 800? Huh? I don't get that. And the strangeness continues as you go down ~720-730.
The score distributions at the top were similar but less extreme
for reading and
writing.
(That same strange effect happens in the scores below but nearish to the average for all three tests.)