Camara, W. J., Copeland, T., & Rothschild, B. (1998). Effects of extended time on the SAT I: Reasoning test score growth for students with disabilities . College Entrance Examination Board. https://eric.ed.gov/?id=ED562679

College Board Report No. 98-7 New York: The College Board

Students took the test with extended-time.

Data were analyzed for 706,537 students without disabilities who took the test twice under standard conditions, 4,479 (0.6% of sample) students with learning disabilities (LD) who took the test twice under extended time conditions, 3,836 students with LD who took the test first under standard conditions, and then under extended time conditions, and 784 students with LD who took the test first under extended time conditions, and then under standard conditions.

SAT I was the dependent variable (extant assessment data).

The mean score gain for students with learning disabilities who first took the test under standard conditions and then under extended time was more than three times the mean score gain for students without disabilities taking the test twice under standard conditions and students with learning disabilities taking the test twice with extended time.