Bunney 1976a.

Study characteristics
Methods	This study was carried out in a secondary care setting, and it was open. Intention‐to‐treat analysis was not carried out. This study was conducted in the UK.
Participants	100 participants were recruited: 28 dropped out. Inclusion criteria of the trial Adults and children Ordinary or refractory warts not specified Warts on the hands only
Interventions	Cotton wool bud cryotherapy ‐ 2‐week, 3‐week, and 4‐week intervals The effects of the intervals between freezes were compared up to 12 weeks of therapy.
Outcomes	Outcomes of the trial Cure at 12 weeks
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	This was done using a random (numbers) table.
Allocation concealment (selection bias)	Unclear risk	This was unclear.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Treatments were allocated blind. Quote (page 668): "...the key being held by the hospital pharmacy."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	This was unclear.
Incomplete outcome data (attrition bias) All outcomes	High risk	28/100 participants (page 670) dropped out or withdrew; it was unclear how they were distributed across the intervention groups. Comment: Minimalisation of attrition bias was inadequate. There was a possibility of a high risk of bias.
Selective reporting (reporting bias)	Low risk	All outcomes were reported.