They also tend to perform better in cognitive and linguistic assessments when staff-child ratios are higher. Furthermore, academic development seems to be enhanced by higher staff-child ratios, although there are not many (recent) studies that have investigated this topic (Huntsman, 2008, Sylva et al., A limitation of the research mentioned above is that most findings are almost exclusively correlational, and there have been very few experimental studies (Huntsman, 2008). An experimental study carried out by Chetty et al. (