Taylor 2005.

Study characteristics
Methods	RCT
Participants	156 people having day surgery for "a range of procedures including hernia and varicose veins removal" in England. Dates not given.
Interventions	Group 1: hair removal with a razor (n = 78) Group 2: hair removal with clippers (n = 78) Product details: razors were "standard hospital supply disposable razors", clippers were 3M with disposable heads. Timing of hair removal: the day of surgery. Hair removed by: perioperative staff. Venue for hair removal: day surgery unit.
Outcomes	Primary outcome: participant preferences and skin trauma, identified through interview immediately after hair removal by hospital staff and 2 weeks after surgery by the research team. Secondary outcome: SSI described by participant during follow‐up phone call with research study staff 2 weeks after surgery. Defined as red, pain, swelling, and discharge.
Notes	Study supported by an award from the NATN/3M Clinical Fellowship. No details of conflict of interest.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "random number tables" Comment: consider adequate approach.
Allocation concealment (selection bias)	Low risk	Quote: "allocation cards placed inside sequentially numbered envelopes" Comment: consider adequate approach.
Blinding (performance bias and detection bias) Care providers blinded	Unclear risk	Not reported. Comment: unclear whether care providers were blinded to intervention allocation.
Blinding (performance bias and detection bias) Participants blinded	High risk	Not reported. Comment: participants would have been aware of hair removal method.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not reported. Comment: interviews were carried out by perioperative staff and 1 of the research team who may have known participant allocation groups, plus participants self‐assessed.
Incomplete outcome data (attrition bias) ITT analysis undertaken	Unclear risk	Not reported. Comment: no discussion of whether participants were analysed in the groups to which they had been allocated.
Incomplete outcome data (attrition bias) Drop out rate acceptable	Low risk	Participants who dropped out are accounted for, and participants are distributed evenly across groups. Comment: the number of dropouts was judged to be unlikely to have altered the result, even in a worst‐case scenario (i.e. assuming that those that dropped out developed an SSI).
Selective reporting (reporting bias)	Low risk	Main outcomes reported. Comment: unlikely to be affected by reporting bias.
Other bias	Unclear risk	Comment: no information on the similarity of groups.