Solís‐Cámara 2004.

Methods	Design: Parallel randomised controlled trial Unit of randomisation: Mother/child dyads Follow‐up: 6 months Study dates: No information provided
Participants	Participants: Parents (30 mothers, 10 fathers) of children fulfilling criteria for behavioural difficulties Mean age of parents: 35.3 (SD 6.9; range: NR) years; Mean, SD, range for intervention and control and for mothers and fathers: NR Mean age of child: 3.7 (SD 0.8, range 3 to 5) years; 24 boys and 16 girls; Mean, SD, range for intervention and control: NR Ethnicity: Not reported Number randomised: 40 (intervention 20; control 20) Country & setting: Mexico; recruited from preschool settings Eligibility criteria: Not specified
Interventions	Two conditions: Group‐based parent training (research‐based standardised parenting programme); wait‐list control Duration of intervention: 8 (1.5 hour) sessions over 8 weeks Therapist training: Not reported
Outcomes	Secondary outcomes: Social skills as measured by the Eyberg Child Behaviour Inventory ‐ social behaviour, parent‐reported (negative behaviour not added); parent‐child interaction as measured by a checklist of observations of interactions (IOI ‐ Informe de Observation de la Interaction, back‐translated and validated), observer‐rated Timing of outcomes: Outcomes reported for 6‐month follow‐up Primary outcomes/adverse events: No other outcomes relevant to this review specified
Notes	Level of prevention: Secondary or tertiary Funding: No information provided
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The study investigators reported "people were randomly assigned to two groups using a table of random numbers; subsequently with a toss of a coin it was decided which group was to receive the intervention or control (waiting list)" (p 203)
Allocation concealment (selection bias)	Low risk	The study investigators reported "people were randomly assigned to two groups using a table of random numbers; subsequently with a toss of a coin it was decided which group was to receive the intervention or control (waiting list)" (p 203)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants: It would not have been possible to fully blind participants in this type of study (there is an obvious difference between receiving group training and wait list). No indication of any specific additional measures taken to reduce the risk of bias that might result from differential behaviours by participants were found Personnel: The design of the study meant that personnel delivering the intervention were aware which groups had been assigned to the different study conditions
Blinding of outcome assessment (detection bias) Independent observer reported outcomes	Unclear risk	Information reported insufficiently for a judgement to be made
Blinding of outcome assessment (detection bias) Parent reported outcomes	High risk	Outcome assessments by parents were not blinded as parents were aware of the intervention condition
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	There was no mention of incomplete outcome data. They stated that 50 children and parents were chosen and 10 were excluded before entering the study
Selective reporting (reporting bias)	Unclear risk	It seems that all outcomes were reported, but not with sufficient information
Other bias	Low risk	The study appeared to be free of other sources of bias