Herbert 2011.

Methods	Country: Canada Setting: recruited from 5 public health nursing offices, 8 day care centres and kindergartens on Prince Edward Island. Intervention in the community RCT
Participants	Parents with children younger than 5 years of age exposed to ETS
Interventions	Group sessions held once a week for 3 consecutive weeks, followed by weekly telephone calls for 3 additional weeks Both groups received a brochure on ETS.
Outcomes	Six‐month follow‐up from baseline: • Parent report on the average number of cigarettes smoked in the home daily • Implementation of a total ban on smoking in the household
Type of intervention	Community‐based
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation sequence with block sizes of 4 or 6
Allocation concealment (selection bias)	Low risk	Sequentially numbered opaque, sealed envelopes
Incomplete outcome data (attrition bias) All outcomes	Low risk	9/30 non‐attenders for intervention; ITT analysis done
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Phone interviews conducted and participants asked how they found the programme, so interviewer could not be blind