Singer 1999.

Study characteristics
Methods	Randomised controlled trial; wait list control.
Participants	174 parents/carers of children with a disability participated. 128 in final analysis (56 experimental/72 control).
Interventions	Parent‐to‐parent support. Participants were matched (following interview) to supporting parents who received training in communication skills, local services, and advocacy and support. Participants made initial call to coordinating centre to be matched; thereafter supporting parents were instructed to make a minimum of 4 phone calls to participants over 2 months. Wait‐list control.
Outcomes	Primary Cognitive adaptation; empowerment; coping efficacy Kansas Inventory of Parental Perceptions (source of strength sub‐scale): Measures positive attitude to having a child with a disability. The sub‐scale used is a 7 item self report measure, rated on a 4‐point Likert scale (1‐4). Items are summed to reach total score, which ranges from 7‐28. A higher score indicates greater perceived benefit Behr 1992. Family Empowerment Scale: a 34 item self‐report measure, rated on a 5‐point Likert scale (1=not at all true, to 5=very true). Includes 3 sub‐scales of family, service system, and community/political empowerment. Sub‐scales are aggregates; sub‐scales can be added for total score, which can range from 34‐170. A higher score indicates greater family empowerment. Parent Coping Efficacy Scale: Measures perception of coping ability. A 24 item self‐report measure rated on a 5‐point Likert scale (1= not capable to, 5=capable). Items are average to reach the sub‐scale score or total score. Scores range from 1‐5. A higher score indicates greater feelings of capability Blanchard 1996. Secondary Abstract mentions satisfaction measure but the qualitative analysis (of responses from a small subset of participants) was about possible mechanisms by which the intervention might provide support. See notes. Outcomes were measured at baseline and at 8 weeks following baseline.
Notes	Means and SDs for the empowerment outcome were sought from the author but were not available. The reported ANCOVA "suggests that initial contacts in Parent to Parent do not change parents' perceptions of empowerment". Qualitative data available 24 parents drawn from the pool of subjects who participated in Parent to Parent (12 from intervention, 12 from wait list) completed a standardised telephone interview. Transcribed interviews were coded according to identified themes. These themes pertained to how P2P makes a difference. Degree of satisfaction with intervention was not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Coin toss used
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Unable to blind due to nature of intervention and control.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Post‐test questionnaire asked about amount of contact with support parent, revealing group allocation. Self‐report nature of data collection means this should not have affected outcome assessments by research personnel, but may be bias from participants.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition and exclusions well reported
Selective reporting (reporting bias)	Unclear risk	Statistical analyses reported for all outcomes, but not means and SDs for all outcomes
Other bias	Low risk	No other sources of bias found