Retaking to succeed: Causal evidence on optional course retaking in college

Many colleges permit course retakes, yet their effects on academic success remain largely unknown. We study a four-year university that canceled a grade-replacement policy in 1995 and reinstated it in 2001. Exploiting these policy shifts and the disproportionate retaking response among D/F students relative to C students, we estimate the causal effects of retaking using an instrumental-variables design. Grade replacement substantially increased retaking among students who initially earned D/F grades. We find broadly robust evidence that retaking improves same-subject persistence and subsequent performance among students who continue in the subject. Estimates for university-level retention and four-year graduation are less robust, ranging from positive to no detectable effects. Overall, grade replacement encourages struggling students to retake courses without harming their short- or longer-run academic progress.