Niccols 2008.

Methods	Design: Parallel randomised controlled trial Unit of randomisation: Individual participant Follow‐up: 6 months Study dates: No information provided
Participants	Participants: 76 mothers registering for Right from the Start Parenting Program Mean age of parents: 28.8 (SD 6.2, range 18 to 40) years; mean, SD, range for intervention and control groups: NR Mean age of child age: 8.4 (SD 5.4, range 1 to 24) months; 50% boys; mean, SD, range for intervention and control groups: NR Ethnicity: Not reported Number randomised: 76 (intervention 48; control 28) Country & setting: Canada; single‐site; recruited from mothers interested registering for parent training programme; delivery of intervention not reported Eligibility criteria: Mothers were eligible for the study if they were able to complete questionnaires in English and had not attended any portion of Right from the Start previously
Interventions	Two conditions: Group‐based parent training (Right from the Start); usual primary care (home visit) Duration of intervention: 8 (2 hour) sessions over 8 weeks Therapist training: Psychologists and social workers with additional training
Outcomes	Secondary outcomes: Parent‐child interaction as measured by the Attachment Q‐set, reported by mother. Only a subset of children were evaluated as the test is for babies over 9 months only. The data reported in the study paper could not be used in our review. We requested clarification from study investigators, and received data that could be used in meta‐analysis (Niccols 2008) Timing of outcomes: Outcomes reported for postintervention and 6 months follow‐up Primary outcomes/adverse events: No other outcomes relevant to this review specified
Notes	We are grateful to the study authors for replying to our request of additional data Level of prevention: Primary prevention Funding: Grants from the Hamilton Health Sciences Foundation and the Ontario Mental Health Foundation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A random sequence was generated using a random number table
Allocation concealment (selection bias)	Low risk	Further information from the study investigators indicates that allocation was concealed: "After the pre‐test assessments were completed, the Principle Investigator (me) randomised the participants to one of the two interventions. I did not reveal group allocation information to the research assistants and I instructed the group facilitators, home visitors, and participants not to reveal this information to the research assistants. I maintained group allocation data on a secure computer (mine) and research assistants did not have access to this data until after the study data collection period was completed" (Niccols 2008)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants: It would not be possible to fully blind participants in this type of study (there is an obvious difference between receiving group training plus home visitation and receiving only home visitation). 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 means personnel delivering the intervention would be aware which groups had been assigned to the different study conditions
Blinding of outcome assessment (detection bias) Independent observer reported outcomes	Low risk	There were no independent observer‐rated outcomes
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	High risk	Only a subset of participants were evaluated; the Attachment Q‐set test was only used to evaluate babies over 9 months, excluding more than half of the randomised participants
Selective reporting (reporting bias)	Low risk	We received information from study authors to enable inclusion of data for the relevant outcome measure
Other bias	Unclear risk	Study investigators reported that completers had higher level of education than did non‐completers