Experimental Evidence on Four Policies to Increase Learning at Scale
与加纳政府合作，在低成绩且异质性高的学校中同时测试了四种干预措施（助教辅导、课后补习、小班教学、部分日分层教学），发现这些措施使学习效果提高约0.1个标准差，对女孩效果更大，且效果持续存在。
Abstract We partnered with the Ghanaian government to simultaneously test four methods of increasing achievement—assistant-led remedial pull-out lessons, remedial after-school lessons, smaller class sizes and teacher-implemented partial day tracking—in schools with low and heterogeneous student achievement. The interventions increased student learning by about 0.1 standard deviations, rising to 0.4 standard deviations when adjusting for imperfect implementation, with no effects on attendance, grade repetition or drop-out. Test score increases were larger for girls. Test score gains persisted after the program ended. Assistants implemented the program with higher fidelity than teachers, although their fidelity decreased over time while teacher fidelity marginally improved.