Chen 2016.

Methods	Country: Taiwan Setting: community (schools) Type: RCT
Participants	75 parent and child dyads in 6 elementary schools (grades 3 to 6); school was the unit of assignment
Interventions	Intervention: Parent‐child dyads received an interactive programme comprising 3 weekly group sessions and 1 individual telephone counselling session 4 weeks after group sessions. Control: Written materials related to tobacco information were received by mail 4 times during the same time period instead of the intervention sessions.
Outcomes	Child exposure: urine cotinine as well as parent and child reports of children's exposure to parental smoking Target knowledge change: Aims of intervention were to instil knowledge regarding the mechanism of the harmful effect of ETS, to correct people's perceptions of the smoking patterns that lead to ETS exposure at home, to introduce strategies for reducing ETS, and to assist parent‐child dyads in formulating strategies for maintaining a smoke‐free home.
Type of intervention	Community‐based
Notes	Conflict of interest: none declared Source of funding: National Science Council of Taiwan (NSC97‐2314‐B‐038‐043‐MY3)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	Low risk	21% dropout rate
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Single‐blind; objective measure (cotinine)
Other bias	High risk	Selection bias: differences in participation rates between intervention and control groups. Non‐simultaneous collection of self‐reported data and urine cotinine levels during post‐test 2 may have caused inconsistency in the data.