The SAT and ACT are supposed to predict (with error) the grades a student will get in college and whether he or she will graduate. A recent study found that two of the ACT sections, Science and Reading, have no incremental predictive ability over the English and Mathematics sections
http://www.nber.org/papers/w17119Improving College Performance and Retention the Easy Way: Unpacking the ACT Exam
Eric P. Bettinger, Brent J. Evans, Devin G. Pope
NBER Working Paper No. 17119
Issued in June 2011
NBER Program(s): ED LS
Colleges rely on the ACT exam in their admission decisions to increase their ability to differentiate between students likely to succeed and those that have a high risk of under-performing and dropping out. We show that two of the four sub tests of the ACT, English and Mathematics, are highly predictive of positive college outcomes while the other two subtests, Science and Reading, provide little or no additional predictive power. This result is robust across various samples, specifications, and outcome measures. We demonstrate that focusing solely on the English and Mathematics test scores greatly enhances the predictive validity of the ACT exam.
