Goodman, Joshua, Oded Gurantz, and Jonathan Smith. "Take Two! SAT Retaking and College Enrollment Gaps." HKS Faculty Research Working Paper Series RWP18-031, September 2018.
Data on millions of SAT-takers show only half retake the exam, with even lower retake rates among low income and underrepresented minority students. Scoring below multiples of 100 increases retaking, implying some students have round number target scores. Regression discontinuity evidence finds retaking once improves admissions-relevant SAT scores by 0.3 standard deviations on average. Likely by strengthening college applications, retaking substantially increases four-year college enrollment, particularly for low income and underrepresented minority students. Eliminating disparities in retake rates could close up to 20 percent of the income gap and 10 percent of the racial gap in four-year college enrollment.