This is a commentary on a Cochrane review, published in this issue of EBCH, first published as: Furlong M, McGilloway S, Bywater T, Hutchings J, Smith SM, Donnelly M. Behavioural and cognitive-behavioural group-based parenting programmes for early-onset conduct problems in children aged 3 to 12 years. Cochrane Database of Systematic Reviews 2012, Issue 2. Art. No.: CD008225. DoI: 10.1002/14651858.CD008225.pub2.