Argueta 1980.

Methods	RCT
Participants	299 women requesting sterilisation at the Asociacion Demografica Salvadorena, San Salvador
Interventions	Spring‐loaded clip versus tubal ring all laparoscopy. All under local anaesthesia and intravenous sedation
Outcomes	Operative morbidity, technical failures and difficulties, failure rates, complaints
Notes	Participant and postoperative evaluation blinding 1 surgeon performed all surgical procedures on an outpatient basis
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation not specified
Allocation concealment (selection bias)	Unclear risk	Assessed as a 'B' study (unclear allocation concealment) in original review
Blinding (performance bias and detection bias) All outcomes	Low risk	Participants and postoperative evaluators were blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	In the clip group 54 women (36%) and 60 (40%) in the ring group were lost to follow‐up at 24 months
Selective reporting (reporting bias)	Unclear risk	Unable to determine
Other bias	Low risk	Women had similar socio‐demographic characteristics