Rao, N., Sun, J., Wong, J.M.S., Weekes, B.S., Ip, P., Shaeffer, S., Young, M.E.,  Bray, M., Chen, E., & Lee, D. (2013).  Early childhood development and cognitive development in developing countries: A rigorous literature review (pp. 101). DFID, UK Government.  

This review assembles extant evidence that will help determine how, why, and under what conditions Early Childhood Development (ECD) interventions in developing country contexts are effective in promoting cognitive development. Typical cognitive development can be defined broadly as expected gains in language, thinking and understanding. Atypical development can be characterised as a delay in expected gains. Our primary motivation was to determine: (i) type(s) of ECD interventions that are effective in attaining typical milestones and can be relatively easily scaled up in different developing country contexts; (ii) the minimum “dosage” of intervention needed to achieve sustainable gains in children’s cognitive development considering their expected milestones; (iii) the best ways to support and involve parents, extended family members and the community in promoting early learning; (iv) characteristics of effective change agents; and (iv) conceptual models that best explain ways to promote cognitive development, school readiness and learning achievement.