Description of the condition
A large proportion of children under five years of age in high-income countries experience significant non-parental care. Specifically, an estimated 80% of children in the United States regularly attend day care (NICHD ECCRN 2006), with similar figures reported in the United Kingdom and Australia (CCCH 2009; Smith 2010). In addition, almost 50% of children aged three to four years in the United States are in full-time day care (at least 35 hours a week) (Capizzano 2005). Parents often choose day care for economic reasons (for example, to enable them to work, look for work, or study) (Smith 2010). For the estimated 20% of single-parent families in high-income countries (OECD 2010), this may be particularly pertinent. In addition, parents might choose day care to improve their child’s social and academic skills before entry into formal schooling (Lamb 2006). Finally, centre-based day care can also be the setting for early interventions to target and enhance the social, cognitive, and academic development of disadvantaged young children (Campbell 2001).
Description of the intervention
Day care for children in high-income countries takes various forms, and may serve multiple purposes. For children under three years old, services tend to be care-oriented and include care by professionals, childminders, and day nurseries. For children aged three years and older, day care provision has more focused educational aims and includes preschools, playgroups and nursery classes (Melhuish 2004). The quality, quantity, and type of day care service appear to be differentially related to child outcomes (NICHD ECCRN 2005; Belsky 2007). Therefore, whilst there is an increasing overlap between education- and care-focused services, it is important to distinguish between studies assessing children under three years and children older than three years, as the nature of the services provided and results may differ. It is also important to distinguish between formal centre-based care (for example, in nursery schools or preschools) and informal care (for example, care by an ex-partner or grandparent) and consider whether the effectiveness of provision differs across settings, including rural versus urban settings or areas of high versus low socioeconomic status (Smith 2010). In addition to differences across settings and type of provision, the explicit purposes for day care can also differ. First, day care enables parental, and specifically maternal, employment. Provision of day care is correlated with increased female labour force participation in high-income countries (Gelbach 2002; Esping-Andersen 2009). Second, day care may also impact on the long-term cognitive and socioemotional development of children, particularly for children from deprived homes (Dearing 2009).
How the intervention might work
Research over many decades has highlighted that the reasons why day care is provided and the mechanisms by which it affects children’s development vary. First, a considerable body of research has investigated whether day care disrupts secure mother-child attachment, which could have long-term developmental consequences for children (Ainsworth 1978; Sroufe 1999). However, day care may serve to enhance the early physical and emotional environment of children, which could be beneficial for children growing up in otherwise impoverished or adverse circumstances. Some studies have found that day care directly affects children’s psychosocial outcomes, including improved social competence (for example, Clarke-Stewart 1994; Balleyguier 1996), which may have lasting effects for mental health outcomes over a lifetime (Shonkoff 2011)). However, other longitudinal studies have found that more time in day care predicts higher levels of externalising behavior, including aggression and non-compliance (NICHD ECCRN 2006; Philips 2006; Belsky 2007).
Second, day care may serve to directly enhance child outcomes via cognitive development, which may have collateral effects on future educational attainment and adult outcomes. Specifically, school readiness and cognitive capacities appear to be enhanced by structured activities, psychosocial stimulation (NICHD ECCRN 2006), and responsive, verbally articulate staff within day care settings (Melhuish 2004). High quality centre-based care has also been linked to improved language development (Clarke-Stewart 1987; Schliecker 1991). In particular, language learning appears to be facilitated in day care settings when children are afforded more opportunities to interact verbally with adults and peers. Longitudinal studies have also demonstrated that early experience of high quality day care as part of multi-component interventions, particularly by low income children, predicts better academic outcomes, higher rates of employment, and less adult criminal activity (for example, Schweinhart 1993; Campbell 2001). At the same time, some studies have also found poorer language development to be associated with increased day care experience (Brooks-Gunn 2002; Bainbridge 2003). Indeed, low quality day care settings may see large numbers of children cared for by highly stressed staff, thereby reducing the potential effectiveness of day care as an intervention to improve child psychosocial or cognitive outcomes (Raver 2004).
Finally, day care is typically offered as a means to improve household income. Mothers may be able to fully participate in the labour market when they feel their children are secure and cared for (Vandell 2002; Melhuish 2004). Indeed, provision of day care is correlated with increased female labour force participation in high-income countries, and an earlier return to the workforce after pregnancy (Brooks-Gunn 1994; Gelbach 2002; Esping-Andersen 2009). There is also likely to be a range of indirect effects of improved household income on child outcomes, including improved nutrition and a more enriched home environment.
Why it is important to do this review
A significant proportion of children in high-income countries under the age of five years experience significant non-parental day care within formal and informal settings (Melhuish 2004; NICHD ECCRN 2006; Smith 2010). It is therefore important to evaluate the effects of day care on the cognitive, linguistic, educational, socioemotional, attachment, and physical health outcomes of children and its impact on parental employment and family income. The only Cochrane review on the topic was carried out a decade ago (Zoritch 2000) and an up to date assessment of the state of the evidence is needed. Furthermore, the previous review included co-interventions beyond day care (such as parent training and home visits), limiting conclusions regarding the effects of day care services alone. To best understand its effects, the intervention of centre-based day care must be isolated from additional programme components such as home visits and other interventions that are not centre-based. The effects of additional components that are centre-based (for example, educational programmes) also need to be analysed. Finally, possible social and economic confounding variables must be controlled for, as specified in the content of this protocol. A new review will guide policymakers and parents in decision-making about centre-based day care for children under five years old.