“…Table 4 summarizes mean effect sizes and p values for all 11 categories of treatments. The next largest means are for treatments that include teacher training (0.12), modify the size or composition of learning groups (0.12), or distribute (Banerjee et al, 2007;Friedman et al, 2010;Lucas, McEwan, Ngware, & Oketch, 2014). Class size reduction is often implemented in tandem with a contract teacher intervention (Bold et al, 2012;Duflo, Dupas, et al, 2012;Muralidharan & Sundararaman, 2010a), complicating efforts to isolate its effects.…”