Remediation has long been a costly way to address the misalignment between K-12 and higher education. In 2011, the California State University (CSU), the nation's largest public four-year university system, enacted "Early Start," requiring students needing remediation to enroll in such courses in the summer before their freshman year. We estimate the impact of Early Start summer remediation relative to both traditional fall remediation and relative to no remediation at all. Our results suggest Early Start summer remediation has not improved student performance or persistence relative to either alternative. As many states move away from remedial courses altogether, there is continued need for both innovation and for evidence in policy and practice to improve college readiness and success. [This paper was published in "Journal of Policy Analysis and Management" v39 n2 p348-375 Spr 2020 (EJ1249962).]