Who makes the ACT-SAT conversion?

ACT4
Sat, 01 Dec 2007 11:12:30 +0000

OK, so now we have three methods for comparing SAT scores to ACT scores. The first is the “Concordance Between ACT Assessment and Recentered SAT I Sum Scores” study completed in the fall of 1997. This is the standard most people use today. It was based on an analysis of 100,000 students who took both the ACT and the SAT in 1995. The bulk of the students come from the states of Florida and Texas, as well as data provided by University of California, Duke, Ohio State, Ball State, U of Illinois, Northwestern, U of South Carolina, Texas A&M, U of Texas, Baylor, Rice, Prairie View A&M, U Maryland, & Stephen Austin.

This study, although thorough, is based on data that is more than 12 years old, doesn’t reflect changes made to both the ACT and SAT over the past 12 years, and is heavily dominated by students from one state, Texas.

The second approach is the “percentile equivalent” which looks at recent test results and compares percentiles. i.e. if 95th percentile for the SAT is 1380 (CR + M) and 95th percentile for the ACT is 29, then a 1380 is equivalent to a 29. (By comparison, the concordance table says that a 1380 is equal to a 31).

The current percentile tables reflect a national group of students, with roughly 1.5 million having taken the SAT and roughly 1.2 million having taken the ACT. Many students take both exams.

The third approach is looking at empirical data provided by schools and comparing 25th & 75th percentile SAT scores to 25th & 75th percentile ACT scores. This approach provides a “quick & dirty” estimation of how schools actually compare the two tests. For a school that is indifferent between the SAT and ACT, a 25th percentile student for one test should be equal to a 25th percentile student for the other test. Clearly this is not a rigorous analysis because it is based on limited publicly available data, but it still has validity.

The results from this approach more closely match the “percentile equivalent” method.

The conclusion I draw is that the standard method in use today is the least accurate and should be recalibrated.