Irvine 1999.

Methods	Parallel randomised controlled trial.
Participants	Participants: families of at‐risk middle school students. Sex: both mothers and fathers (no further information). Age of parents: intervention: 36.6 years (SD 5.4) mothers; 39.3 years (SD 7.1) fathers; control: 37.7 years (SD 6.97) mothers; 39.7 years (SD 7.07) fathers. Unit of allocation: individual family. Number randomised: 303 (151 intervention; 152 control). Number used in analysis: 241 (106 intervention; 135 control) at post‐intervention; 161 (67 intervention; 94 control) at 6 month follow‐up; 109 (51 intervention; 58 control) at 12 month follow‐up. Country & setting: USA; multi‐site (n=8); recruited from community settings; intervention delivered in the community. Inclusion criteria: students with more than three risk factors referred by school or by social service agency staff; the risk factors were: behavioural, externalising, substance use, deviant peer associations, academic deficiencies, and family stress. Exclusion criteria: families currently receiving other treatment. Ethnicity: 88% Caucasian. Baseline characteristics: there were no significant differences between conditions on family status, education, cultural background or target child's gender.
Interventions	Two condition: adolescent transition programme (behavioural parenting programme); wait‐list control. Duration of intervention: 12 weeks. Duration of trial: 4 years. Length of follow‐up: 3 months, 6 months; 12 months.
Outcomes	Depressive symptoms (Beck Depression Inventory).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Trial investigators report that families "were randomly assigned to a condition immediately following their recruitment" (page 813). Information from trial investigator (email from B Irvine to NH on 22 Oct 2010) indicates that a random numbers table was used.
Allocation concealment (selection bias)	Low risk	Information reported insufficient for a judgement to be made. Information from trial investigator (e‐mail from B Irvine to NH on 22 Oct 2010) indicates that allocation concealment was achieved through use of a central allocation facility.
Blinding (performance bias and detection bias) Participants	High risk	Review authors judged that it would not be possible to fully blind participants in this type of study, and found no indication of any specific additional measures taken to reduce the risk of bias that might result from differential behaviours by participants.
Blinding (performance bias and detection bias) Personnel	High risk	Information reported insufficient for a judgement to be made. Information from trial investigator (email from B Irvine to NH on 22 Oct 2010) indicates that personnel were not blinded.
Blinding (performance bias and detection bias) Outcome assessors	Low risk	Information reported insufficient for a judgement to be made. Information from trial investigator (email from B Irvine to NH on 22 Oct 2010) states that the term 'outcome assessors' was not generally relevant to this study but that "most data were collected via mailed parent surveys". Phone interviewers "did know the allocation status" but "coders of the phone interview recordings did not know the allocation status".
Incomplete outcome data (attrition bias) All outcomes	Low risk	Rates of attrition at post‐treatment were 45/151 (30%) in the treatment group and 17/152 (11%) in the control group, and at 6‐month follow up were 84/151 (56%) in the treatment group and 58/152 (38%) in the control group. Although numbers of missing data were not balanced between conditions, trial investigators conducted a comparison on each of the dependent variables, looking for a main effect between study drop out and the remaining participants across all of the subsequent time points and found that the study dropouts and the parents who remained differed on only one variable (the laxness scale of the PSA that measures parental limit setting).
Selective reporting (reporting bias)	Low risk	Review authors judge that the published report includes all expected outcomes, including those that were pre‐specified.
Other bias	Low risk	The study appears to be free of other sources of bias.