Every school reports the "middle 50%" for SAT scores. What exactly does this mean? Does this mean 50% of all scores, or 50% of all students? Because if it's 50% of all students and not scores, there are probably a lot more scores at the lower end of the range. For example, it a school says the middle 50% is 1200 to 1350, is it likely that most of the scores within this range are closer to 1200 than to 1350? Does my question make sense?
tokenadultPosts: 17,473Super ModeratorSenior Member
The count is a count of students WHO TOOK THAT TEST. Below, I simplify my sentences by saying "one quarter of the students" when I should really say "one quarter of the students in that class who submitted scores from that test." NACAC prefers that colleges report scores this way, by interquartile range rather than by medians, because this is more informative. So, to give two examples,
SAT Critical Reading: 460 - 580
SAT Math: 460 - 590
SAT Writing: 430 - 550
ACT Composite: 20 - 25
The meaning is that at Harvard, a quarter (or more) of all enrolled students in the current freshman class had SAT critical reading scores of 800 (whew!), a quarter (possibly NOT the same quarter) of students had an SAT math score of 790 or higher, a quarter (again, maybe not the same quarter) had a writing score of 790 or higher, and a quarter (as before, not the same quarter as for the three other reported test sections) had an ACT score of 35 or higher. And, on the other hand, at Harvard one quarter of all enrolled freshmen this year have critical reading scores of 700 or below, and one quarter have math scores of 700 or below, and one quarter have writing scores of 690 or below, and one quarter have ACT scores of 31 or below. In general, most enrolled students at Harvard have high scores, and those who have the lowest scores are probably amazing in other ways.
By contrast, at the University of Nevada Reno, with a different size freshman class, one quarter of the enrolled class (which thus is a different number of students from one quarter of Harvard's class) have critical reading scores of 580 or above. It is perhaps possible that EVERY student at UNR has a lower score than ANY student at Harvard. Similarly, one quarter of UNR students have a math section score of 590 or above, and one quarter have a writing score of 550 or higher, and one quarter have an ACT composite of 25 or higher. I think you can work out for yourself what the bottom quartile scores mean. You are correct in figuring that it's theoretically possible that even at Harvard there could be some students with a section score on the SAT as low as the scoring scale goes, with the interquartile ranges still being true as reported above, but I doubt that's what actually happens at Harvard. The 25th percentile does NOT set a lower bound for the lowest possible score with which an applicant might be admitted.
Thank you, Tokenadult. OK so I understand about the quarter above and the quarter below. What I wonder about it the 50% in between. It might be somewhat misleading if a school says 50% of their scores are, for example, between 460 and 580 when in fact most of them were really between 460 and 500. I guess what I am wondering, does anybody know if the scores within the 50% range are generally on the high side or the low side - or neither? Maybe the are scatttered evenly throughout. And I suppose at Harvard there are many more on the high side than at University of Nevada at Reno.
College bound, I either don't understand your question or you don't have a grasp on what these numbers mean. It's not misleading, and it's not on the high side or low side: it is what it is. Those are the scores of the middle 50% of students, whether it's Reno or Harvard. If a school gives ranges of 460-580, then that's it, end of story, it's not 460-500. There's nothing subjective or open to manipulation about it (well aside from choosing whether to report SAT v. ACT for individuals on the part of colleges, but that's besides the point).
tokenadultPosts: 17,473Super ModeratorSenior Member
Yes, the AP statistics teachers email list, to which I subscribe, talks a lot about what you DON'T know if you know the interquartile statistics. Many distributions are possible for that middle 50 percent group of students between the 25th percentile on scores and the 75th percentile.
It is actually the first hit in a Google search "What is middle 50%". While the definition seems intuitively obvious, I suspect many assume that the scores within the middle 50% are evenly spread when in fact they may be clustered at one end of the range or the other.
In most cases, the number refers to ENROLLED students who took the test. One would think that the enrolled student population would be somewhat lower than the ACCEPTED student population (i.e., the middle 50% of students accepted would be higher than the numbers reported).
If it's a normal distribution, you would expect to see most scores near the median and smaller numbers at either end, but without seeing the actual data, who knows.
Replies to: What does middle 50% really mean?
http://collegesearch.collegeboard.com/search/CollegeDetail.jsp?collegeId=1251&profileId=6
SAT Critical Reading: 700 - 800
SAT Math: 700 - 790
SAT Writing: 690 - 790
ACT Composite: 31 - 35
http://collegesearch.collegeboard.com/search/CollegeDetail.jsp?collegeId=3261&profileId=6
SAT Critical Reading: 460 - 580
SAT Math: 460 - 590
SAT Writing: 430 - 550
ACT Composite: 20 - 25
The meaning is that at Harvard, a quarter (or more) of all enrolled students in the current freshman class had SAT critical reading scores of 800 (whew!), a quarter (possibly NOT the same quarter) of students had an SAT math score of 790 or higher, a quarter (again, maybe not the same quarter) had a writing score of 790 or higher, and a quarter (as before, not the same quarter as for the three other reported test sections) had an ACT score of 35 or higher. And, on the other hand, at Harvard one quarter of all enrolled freshmen this year have critical reading scores of 700 or below, and one quarter have math scores of 700 or below, and one quarter have writing scores of 690 or below, and one quarter have ACT scores of 31 or below. In general, most enrolled students at Harvard have high scores, and those who have the lowest scores are probably amazing in other ways.
By contrast, at the University of Nevada Reno, with a different size freshman class, one quarter of the enrolled class (which thus is a different number of students from one quarter of Harvard's class) have critical reading scores of 580 or above. It is perhaps possible that EVERY student at UNR has a lower score than ANY student at Harvard. Similarly, one quarter of UNR students have a math section score of 590 or above, and one quarter have a writing score of 550 or higher, and one quarter have an ACT composite of 25 or higher. I think you can work out for yourself what the bottom quartile scores mean. You are correct in figuring that it's theoretically possible that even at Harvard there could be some students with a section score on the SAT as low as the scoring scale goes, with the interquartile ranges still being true as reported above, but I doubt that's what actually happens at Harvard. The 25th percentile does NOT set a lower bound for the lowest possible score with which an applicant might be admitted.
Collegebound: I doubt that info is published for any school. It might follow a bell curve, but that is purely speculative.
In most cases, the number refers to ENROLLED students who took the test. One would think that the enrolled student population would be somewhat lower than the ACCEPTED student population (i.e., the middle 50% of students accepted would be higher than the numbers reported).
If it's a normal distribution, you would expect to see most scores near the median and smaller numbers at either end, but without seeing the actual data, who knows.