The impact of a story-based intervention on language, literacy, and cognitive development in South African pre-schoolers: randomised controlled trials for two language groups

• Teacher-delivered randomised controlled trials of South African preschoolers. • Story-based intervention designed to improve foundational skills for reading. • Intervention implementation quality influenced learning of target vocabulary. • Post-intervention, more treatment children on track in key developmental domains. • Baseline performance predicted performance gains for treatment and control groups. Literacy rates in South Africa are low and many children start school without the requisite levels of emergent language and literacy skills needed to succeed. We report two RCTs of a story-based intervention delivered by preschool teachers to two language groups of children from low income backgrounds (isiXhosa: N children =82, N teachers =20; Afrikaans, N children =118, N teachers =24). The story-based intervention involved a 36-week programme, of 2-week cycles, each using a different culturally-appropriate story in the target language with activities designed to foster emergent language and literacy skills. Training for the teachers before and during the intervention was provided. The post-intervention assessment took place after 26 weeks. For both language groups (compared with the corresponding control group), the intervention had a positive impact on vocabulary taught in the programme and also developmental status across key learning domains. For early language and emergent literacy measures, baseline ability was the most consistent predictor for all outcome measures, with additional important contributions of initial vocabulary for some measures. This study demonstrates the feasibility of conducting gold-standard randomised controlled trials in low-resource settings. We draw on the data to set out practice and policy recommendations, critically the need to support school and literacy-learning readiness in homes and preschools, to enhance practice and children’s outcomes.