Russell 1987a.

Methods	See Russell 1987
Participants	See Russell 1987
Interventions	See Russell 1987
Outcomes	See Russell 1987
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	See Russell 1987
Allocation concealment (selection bias)	Unclear risk	See Russell 1987
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	See Russell 1987
Selective reporting (reporting bias)	Unclear risk	See Russell 1987
Other bias	Unclear risk	See Russell 1987