Martine van der Pluijm

155 General discussion INTRODUCTION Already in early childhood, children differ significantly in their language acquisition, as can be seen in variations of vocabulary sizes (e.g., Ariaga, Fenson, Cronan, & Pethick, 1998; Hoff, 2006; Kuiken et al., 2005). These language delays affect children’s school performance and may cause literacy gaps during elementary school (Gilkerson et al., 2018; Walker, Greenwood, Hart, & Carta, 1994). Comprehensive support of children at schools and at home, acknowledging families’ homes as the most influential environment for child development, is considered a promising strategy to closing young children’s language and literacy gaps (Crosnoe et al., 2010). Meta-studies have shown effects on child language and literacy outcomes of Family Literacy Programs (FLPs) targeting the home environment by (e.g., Van Steensel, Fikrat-Wevers, Bramer, & Arends, 2019), dual programs that target children and parents both at school and at home (e.g., Blok, Fukkink, Gebhardt, & Leseman, 2005), and School-Family Partnership (SFP) programs that connect home and school by (e.g., Wilder, 2014). No effects have been reported for the single focus of the Dutch school approach Early Childhood Education and Care (ECEC) that targets child development at schools and has no integrated parent component (Fukkink, Jillink, & Oostdam, 2017). In addition, fewer effects have been found for low-SES (e.g., low education) groups of parents in programs targeting the home environment and improving partnerships between schools and families, leading to an appeal for tailoring programs to the needs of diverse groups of parents (e.g., Manz, Hughes, Barnabas, Bracalielo, & Ginsburg-Block, 2010; Van Steensel, Herppich, McElvany, & Kurvers, 2012). Little attention has been given to how programs can be tailored to the specific needs of lower- educated parents. Parental education is the most important explanation for young children’s language development (Golinkoff et al., 2019; Hoff, 2013; Mesman, 2010; Rowe, Denmark, Harden, & Stapleton, 2016) and is a guiding factor for governmental funding of schools in the Netherlands (Roeleveld, Driessen, Ledoux, Cuppen, & Meijer, 2011). Parental education levels are defined as low when they have a maximum of primary education (very low) or lower secondary education (low), which is in line with the definition of the OECD (2015, p. 15). Additionally, it is unclear how teachers can acquire the required skills to work with lower- educated parents. Previous studies have shown that teachers are insufficiently prepared to work with parents in disadvantaged contexts and low education levels (e.g., Bakker, Denessen, Dennissen, & Oolbekkink-Marchand, 2013; Lusse, Notten, & Engbersen, 2019). This thesis addresses the need for ecologically valid approaches for teachers to support lower- educated parents and stimulate young children’s language development by connecting the school and home environments. To contribute to this aim, we need to improve our understanding of existing SFP and FLP programs and their effects. We also need to investigate