Terpstra 2012.

Methods	Included as process evaluation Intervention study design: quasi‐experimental design, pre‐post follow‐up, control group Unit of allocation: school Process evaluation methods: multi‐variate analysis
Participants	Country: USA Age of children: mean age, 12.52 in the intervention group and 12.10 in the control group Child characteristics (BME/SES): 44% of intervention children and 56% of control group children were Latino; average annual income was less than $20,000 Asthma status: asthmatic only Intervention recipients: children and parents
Interventions	School type: 2 middle schools Intervention description: children received skills training addressing topics such as how to use a peak flow meter. These sessions took place over 6 weeks. Parents received a newsletter that was centred on an important theme identified during the research Control description: equivalent intervention in which children received the intervention but parents did not receive the newsletter Theoretical framework: social cognitive theory
Outcomes	Core processes evaluated (child level): attrition, dosage, adherence
Notes	Process evaluation category: integrated Breadth and depth: neither broad nor deep Voice of children given prominence: not featured Funding source: American Lung Association
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	N/A
Allocation concealment (selection bias)	Unclear risk	N/A
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	N/A
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	N/A
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	N/A
Selective reporting (reporting bias)	Unclear risk	N/A
Other bias	Unclear risk	N/A
Transparent and clearly stated aims	Unclear risk	Study aims were not clearly stated
Explicit theories underpinning and/or literature review	Unclear risk	Some theory and supporting literature were provided, but why a newsletter was used was not explained
Transparent and clearly stated methods and tools	Low risk	All tools were clearly described
Selective reporting	High risk	This was not considered ‐ particularly the absence of measures showing whether people did receive the newsletter Also, as acknowledged by study authors, not only caregivers received the newsletter
Harmful effects	Unclear risk	This was not recorded, and the paper included no information on child outcomes
Population and sample described well	Unclear risk	School characteristics were poorly described
Continuous evaluation	Low risk	Pre‐post assessment was carried out
Evaluation participation equity and sampling	High risk	No child input was included
Design and methods overall approach	High risk	Low breadth of scope was evident, for example, not all stakeholders and not all outcomes were reported
Tools and methods of data collection reliable/credible	Low risk	Tools used for data collection were appropriate for the data
Tools and methods of data analysis reliable/credible	Low risk	How conclusions were reached is clearly explained
Performance bias/neutrality/credibility/conformability	Unclear risk	Absence of 'other' stakeholders who received the newsletter might reduce credibility; absence of any child outcomes certainly does reduce credibility
Reliability of findings and recommendations	Unclear risk	Intervention did not work
Transferability of findings	High risk	Information provided is not rich enough to support a similar study
Overall risk of bias of process evaluation	High risk	Intervention was unsuccessful