Kegler 2015.

Methods	Country: USA Setting: community (2‐1‐1 callers) Type: RCT
Participants	498 2‐1‐1 callers who were either smokers living with at least 1 child or other non‐smoker, or non‐smokers living with a smoker, and smoking was allowed in the home. Callers to 2‐1‐1 are disproportionately low income, unemployed, and uninsured, and have received fewer years of education relative to the general population.
Interventions	Intervention: Smoke‐Free Homes intervention consisted of 3 mailings and 1 coaching call, based on a theme of "Some things are better outside", with content focused on 5 steps to create a smoke‐free home. The intervention was delivered over a 6‐week period at 2‐week intervals, first as a mailing, then as a coaching call, and finally as 2 additional mailings. The coaching call used motivational interviewing. Control: measures alone
Outcomes	Child exposure: home smoking ban (self‐report), validated with air nicotine levels Target behaviour change: smoking away from home
Type of intervention	Community‐based
Notes	Conflict of interest: unclear Source of funding: National Cancer Institute's State and Community Tobacco Control Research Initiative (U01CA154282)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	'Simple' (not block) randomisation, but method not described in detail
Allocation concealment (selection bias)	Unclear risk	Not specified
Incomplete outcome data (attrition bias) All outcomes	Low risk	83.1% completed 3‐month data collection, and 79.1% completed 6‐month data collection.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	University‐based research assistants blinded to study condition collected outcome data at 3 and 6 months post randomisation; objective measure was also used.