Table 2

The quality rating of each study based on the Cochrane risk of bias assessment

Random sequence generationAllocation concealmentBlinding (participants and personnel)Blinding (outcome assessment)Incomplete outcome dataSelective reportingOther sources of bias
Angeles et al46UnclearUnclearHigh riskUnclearLow riskLow riskLow risk
Baird et al45UnclearUnclearUnclearUnclearLow riskUnclearLow rIsk
Fernald and Gunnar43High riskHigh riskUnclearUnclearUnclearHigh riskHigh risk
Filmer and Schady52High riskHigh riskUnclearUnclearLow riskUnclearLow risk
Kilburn et al40UnclearUnclearLow riskUnclearLow riskUnclearLow risk
Kilburn et al51UnclearUnclearUnclearUnclearUnclearLow riskUnclear
Macours et al50Low riskUnclearUnclearUnclearUnclearLow riskLow risk
Özler et al48UnclearLow riskUnclearUnclearLow riskLow riskHigh risk
Ozer et al42High riskHigh riskUnclearUnclearLow riskLow riskHigh risk
Paxson and Schady49High riskHigh riskUnclearUnclearHigh riskUnclearHigh risk
Shangani et al47High riskHigh riskUnclearUnclearUnclearLow riskHigh risk
Tozan et al39UnclearUnclearUnclearUnclearUnclearLow riskHigh risk