A Cochrane review included 22 RCTs and 2 quasi-RCTs evaluating the effectiveness of brief (4 to 12 weeks) group-based parenting programmes aimed at improving the emotional and behavioural adjustment of children aged up to 3 years 11 months (maximum mean age 3 years 11 months; age range one to five years). Group-based parenting programmes did not reduce overall emotional and behavioural problems based on total parent-reported data assessed at postintervention (SMD -0.67, 95% CI -1.43 to 0.09; 3 studies, n=221). The results of data from subscales show evidence of reduced total externalising problems (SMD -0.23, 95% CI -0.46 to -0.01; 8 studies, n=989, moderate quality evidence). Single study results show very low quality evidence of reductions in externalising problems hyperactivity-inattention subscale (SMD -1.34; 95% CI -2.37 to -0.31; n=19), low quality evidence of no effect on total internalising problems (SMD 0.34; 95% CI -0.12 to 0.81; n=73), and very low quality evidence of an increase in social skills (SMD 3.59; 95% CI 2.42 to 4.76; n=32), based on parent-reported data assessed at postintervention. There was an impact on parent-child interaction in terms of reduced negative behaviour (SMD -0.22, 95% CI -0.39 to -0.06; 7 studies, n=941, moderate quality evidence), and improved positive behaviour (SMD 0.48, 95% CI 0.17 to 0.79; 4 studies, n=173, moderate quality evidence) as rated by independent observers postintervention.
Post-intervention data provided evidence of short-term effectiveness for both parent reports of children's emotional and behavioural adjustment (SMD -0.25, 95% CI -0.45 to -0.06; statistical heterogeneity IComment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment) and by indirectness (lack of follow-up data).