ACT vs. SAT Scores

Converting an ACT score to an SAT score isn’t like converting miles to kilometers. There’s no “right answer”, no exact value of what an ACT score is worth in SAT points. There are a lot of factors at work here, and several different ways to look at the data.

As any simple web search will show you, there are many SAT-ACT conversion tables out there. Many of these tables are taken from score comparison data available on the College Board website (see Table A). This chart is based on a study of test scores from 1994 to 1996. It’s a comparison based on skill: if you get score X on the SAT, you’ll get score Y on the ACT. It’s probably the most reliable chart out there in that it’s the product of a rigorous scientific study commissioned by people who know about this sort of thing. However, it uses data from the old SAT. The College Board will tell you that the scores should be comparable, but let’s see if there’s any fresher data available.

Fresher data is readily available in the form of percentiles. Both the SAT and ACT publish tables of the percentiles of test-takers who achieved a particular score. So we took data from 2005 to 2007 and matched up the scores on the two tests that correspond to the same percentile (see Table B). This chart shows signifi¬cantly higher SAT scores for corresponding ACT scores than the College Board table does. The problem is that this is an unsci¬entific study, so there could be other factors contributing to the score distribution.

Both these charts seek to equate scores based on the ability of students: a student who gets score X on one test is likely to get score Y on the other. But this overlooks why these scores matter at all: college admissions. These charts don’t tell us the value of the scores with respect to actual admissions decisions. Perhaps colleges treat the tests differently. Perhaps a college will accept a student in the 80th percentile of the SAT but require the 85th percentile of the ACT, or vice versa.

So we took a look at the college admissions data in the 2008 U.S. News and World Report guide and matched the SAT and ACT scores of incoming students at each college. We found those numbers were somewhat in between the previous two charts. This chart has the same concern about scientific validity as Table B, but it’s the best way to directly gauge how much a score is actually worth to colleges.

It’s all a bit moot. Scores are variable enough that you should think of a score as a range, rather than an absolute number. These charts should give you a good idea of how SAT and ACT ranges compare, in general. But as always, the best source of information is from the colleges themselves. Look up the par¬ticular schools you’re interested in and find out what their SAT and ACT ranges are. That’s the best way you can see how well you stack up against your competition.

[1]Average SAT score was used when percentiles for the two tests did not exactly match up, which is why some SAT scores here end in a “5″. For example, a score of 20 on the ACT is the 48th percentile, but the SAT lists no 48th percentile: a 1000 is the 47th and a 1010 is the 49th. So we matched 20 ACT to 1005 SAT.