This USA based meta-analysis looked at the association between parenting and outcomes for children with developmental disabilities. The authors point out that despite there being an extensive literature supporting the positive relationship between positive parenting and child outcomes for typically developing children, there has been little work to analyse the literature specific to children with developmental disabilities.

What they did to carry out a meta analysis of the aggregation of effect sizes across 14 studies which covered 576 participants published between 1990–2008. 41% of the participants were female, 50% had Down syndrome.

A meta-analysis focuses on contrasting and combining results from a number of studies to identify patterns, disagreement or other relationships between those results. The aim of a meta-analysis is to estimate the true effect size of the phenomenon  under study. Single studies may over or under estimate such effect sizes.

They found the random effects weighted average effect size indicated a moderate association between positive parenting attributes and child outcomes.

They were able to discount the effects of publication bias (the tendency to publish positive results over negative or null results. They found the effect sizes to be higher for older parents, younger children, and for those with Down syndrome.

They conclude that their results show a sufficiently large effect size to “provide support for efforts to evaluate and promote effective parenting skills when providing services for young children with disabilities.”

Positive parenting of children with developmental disabilities: A meta-analysis, Taylor Dyches T et al., in Research in Developmental Disabilities 33, 6, 2213-2220