Background: Loose Parts Play (LPP) interventions introduce moveable materials and equipment to children's play spaces to facilitate unstructured, child-led play. Metaanalysis of previous school-based research has shown significant benefits of LPP for physical activity (PA). In the current paper we review the scope and quality of the quantitative evidence relating to cognitive, social, and emotional outcomes. Method: We conducted a systematic search of the literature on LPP interventions for primary school aged children which used quantitative outcome indicators for cognitive, social and/or emotional development. Studies were screened for inclusion by 2 independent researchers and reviewed for content, relevant outcomes and quality indicators. Results: Five studies met the review inclusion criteria. Two studies used a randomised controlled trial design, two studies used quasi-experimental design, and one used an observational design. Outcomes measured focused mainly on social development. With the exception of enjoyment, school satisfaction and self-esteem, emotional outcomes were almost entirely absent. No measures of cognitive or academic outcomes were found. For the studies using control groups, few differences between groups were reported, although 1 study found increased happiness at school and increased odds of reporting being pushed/shoved at playtime associated with intervention. Null results were found for peer acceptance, relational bullying, social competence, social skills, peer group size, and psychosocial quality of life. In the non-controlled study, there were observed increases in co-operative play.

Conclusions: There is insufficient high-quality, quantitative, empirical evidence available to determine whether or not LPP interventions have an impact on children's cognitive, social and emotional development. We conclude our review with some recommendations which we hope will assist future research in this promising field.