The loss of learning that occurs when school is out — aka “summer slide” — is well documented, and disproportionately affects students from disadvantaged backgrounds. But consistent, high-quality summer learning programs can help students succeed academically, according to more than a decade of research conducted by RAND and the Wallace Foundation. Students from five Greenville elementary schools are participating in one such program offered by YouthBASE, a local nonprofit that has provided educational after school and summer programs for at-risk children since 2006.