Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: “Subjects were randomised into one of four groups where randomization was stratified by classroom using a double‐blind approach”
		Comment: Insufficient information to permit judgement
Allocation concealment (selection bias)	Unclear risk	Quote: “Subjects were randomised into one of four groups where randomizations was stratified by classroom using a double‐blind approach”
		Comment: Insufficient information to permit judgement
Blinding of participants and personnel (performance bias)	Low risk	Quote: “Subjects were randomised into one of four groups where randomizations was stratified by classroom using a double‐blind approach.”
		Comment: Adequately done
Blinding of outcome assessment (detection bias)	Unclear risk	Quote: “Subjects were randomised into one of four groups where randomizations was stratified by classroom using a double‐blind approach”
		Comment: Insufficient information to permit judgement
Incomplete outcome data (attrition bias)	Low risk	Comment:
		Group 1: 9/202 loss to follow‐up
		Group 2: 12/213 loss to follow‐up
		Group 3: 17/216 loss to follow‐up
		Group 4: 9/190 loss to follow‐up
Selective reporting (reporting bias)	Unclear risk	Comment: Trial registration not reported. Outcomes specified in the methodology section were reported
Other bias	Low risk	Comment: No other biases detected