Outcomes of early childhood education: Literature review
This literature review was commissioned by the Ministry of Education to provide policy makers with a synthesis of research that analyses the impact of early childhood education (ECE) for children and families.
Author(s): Linda Mitchell, Cathy Wylie and Margaret Carr, New Zealand Council for Educational Research.
Date Published: May 2008
This report is available as a download (please refer to the 'Downloads' inset box). To view the individual chapters please refer to the 'Sections' inset box.
This literature review was commissioned by the Ministry of Education to provide policy makers with a synthesis of research that analyses the impact of early childhood education (ECE) for children and families. It addresses three questions:
- What (short-term and long-term) developmental, educational, social, and economic outcomes are associated with participation in ECE for learners and their families?
- Are different outcomes associated with different population groups and under different circumstances/ contexts? In particular:
- What types of institutional (e.g. differences in educational/care systems, types of services), funding and regulatory arrangements/frameworks are associated with achieving positive outcomes?
- When are adverse impacts more likely and for whom?
- How do different outcomes interact/relate with one another?
- What is the size/significance of the different impacts of ECE? How long do the effects last?
A comprehensive search of material published in education, psychology, public policy, early childhood education, economics, family, and labour market databases was undertaken from May to August 2006, and contact made with key authors in the field.
We include in this review 117 studies reported after 1995, except for some key earlier works. The studies chosen had to meet criteria of having research methods, analysis, and findings sufficiently detailed to provide a sound basis for judgement about the robustness of the conclusions, and information about the characteristics of the context. The evidence demonstrated valid linkages between ECE participation and outcomes.
The studies chosen included longitudinal studies of interventions aimed at disadvantaged children, longitudinal studies of everyday early childhood experiences, analysis of databases comparing children with ECE participation and those without, survey information from parents, and cross sectional studies. The most useful studies analysed the impact of ECE over and above family socioeconomic characteristics linked to differences in children's outcomes, followed children over time, and provided direct data about children's ECE experiences.
Summaries of each of the reports of studies (contained in Appendix A1) were used to synthesise what the research could tell us about outcomes for children (cognitive, learning dispositions and behaviour outcomes, and health), parenting and parent life course outcomes, and maternal employment. A summary of cost benefit outcomes in terms of public expenditure was drawn from two recent literature reviews.
Syntheses of main findings were compiled for each outcome and then brought together to address the three research questions.
An introduction frames the review by:
- examining the issues around the complexity of measuring the outcomes of ECE and establishing ECE's contribution, including the difficulty of isolating the impact of ECE;
- discussing the difficulty of measuring complex outcomes like dispositions and key competencies, although ethnographic studies highlight their importance;
- providing a guide to interpreting statistical effect sizes;
- summarising the overall picture of ECE impacts for each outcome from earlier reviews (pre 1995), and the differences in the size of impact (but not its patterns of effects) for children and parents that occur between studies of substantial "interventions" focused on ECE, and those that look at everyday ECE; and
- describing a model from Cunha, Heckman, Lochner, and Masterov (2005) explaining how ECE effects might endure, and "how skills beget skills".
Key findings from the review
Consistent evidence from a large body of international and New Zealand evidence found ECE participation is positively associated with gains in mathematics and literacy, school achievement, intelligence tests, and also school readiness, reduced grade retention, and reduced special education placement. Medium to large effect sizes on the outcome measures were reported in United States (U.S.). "intervention" studies targeting children from low-income families, and combining good quality ECE with parenting support/education (d=0.32 to 0.81 for mathematics in the short term, 0.19 to 0.44 long term; 0.34 to 0.89 for reading in the short term, 0.17 to 0.44 long term). Small to medium effect sizes from ECE participation were found in studies reporting on everyday ECE experiences (d=0.10 to 0.23 for mathematics in the short term, 0.02 to 0.23 for reading).
Learning dispositions and key competencies are seen as combinations of ability, inclination, and sensitivity to occasion, and refer to the competencies and skills that enable children to keep learning. Learning outcomes in Te Whāriki, the national early childhood curriculum, are summarised as learning dispositions and working theories. Learning dispositions in the studies reviewed included attitudes of perseverance, curiosity, confidence, and social competence such as the ability to work with others. In general, the small number of New Zealand and international studies that examined associations between ECE participation and learning dispositions found positive impacts. Small to medium effect sizes were reported in the high-quality U.S. "intervention" studies (e.g. the Chicago Child–Parent Centre study found d=0.21 for task orientation and assertive social skills, d=0.22 for frustration tolerance, d=0.33 for social adjustment in school in the short term, and d=0.34 for social competence in the long term). The EPPE (Effective Provision of Pre-School Education) study found evidence of "fade out'" of effects by age 7; this did not occur in one New Zealand and one Swedish study following children in everyday ECE and three U.S. intervention studies that followed children long term. Life span modelling (Cunha, Heckman et al.., 2005) emphasises that later, successive, educational contexts are significant influences on the enduring effects of learning orientations and dispositions.
There are mixed findings on the impact of ECE participation on antisocial and worried behaviour. U.S. "intervention" studies found a small reduction in "acting out" behaviours (e.g. d=-0.19) in the short term. There was an indication (one study) that non-maternal care (including ECE), especially an early start before age 17 months, was associated with lower levels of physical aggression for children who were at risk of physical aggression. There was no effect on children not at risk. However, a small number of studies found an early starting age (before age 1 or 2) into low-quality child care was associated with higher levels of antisocial or worried behaviour at the time and at school entry. This could be tempered by subsequent high-quality ECE. Studies with longer time periods do not report antisocial/worried behaviour, indicating that these effects may not last.
The picture on health outcomes is not solid. Except for increasing research on cortisol levels, most studies of health outcomes rely on parent reports, sometimes at a general level, and report short-term outcomes related to current ECE experience. There is a suggestion that children may catch more infections (ear, nose, and throat) through ECE participation, and that young children attending all-day centres may experience higher cortisol levels (symptom of stress). Where centres are good quality, cortisol levels tend to be lower, and ECE experience can decrease cortisol levels where there is parental stress or extremes of emotional expression. ECE programmes that include health support may improve health outcomes.
The outcomes occur for all children across the socioeconomic range. Some additional gains are made by some groups.
Family income. New Zealand and international studies found cognitive gains for children from low-income/ disadvantaged homes could be greater than for most other children in mathematics and literacy, if their ECE centre was of good quality.
English as an additional language. Children for whom English is an additional language, and children from some ethnic minority groups (including Black Caribbean and Black African), made greater progress on early number concepts and pre-reading measures during ECE participation than the white United Kingdom (U.K) children or those for whom English is a first language in the English EPPE study. Overall, these children started with significantly lower scores on language measures (but not nonverbal) and the ECE experience helped them start to catch up with peers in certain areas.
Gender. Gender differences were found in three studies and showed mixed differential gains for boys compared with girls:
- Boys gained more than girls on early number concepts over the time of ECE attendance in the English EPPE study. They also had lower home learning environment scores (measured by parent reports of activities such as playing with letters and numbers, going to the library, reading to the child) than girls.
- Long hours in low-quality child care appeared particularly detrimental for boys' serious externalising (e.g. acting up, self-control, interpersonal skills) behaviour problems, and high-quality more protective than for girls in a U.S.study of ECE experience for children from low-income families.
- In the U.S. Cost, Quality and Child Outcomes study, centres that met professional recommendations regarding teacher education tended to have girls with more enhanced receptive language skills than boys.
Socioeconomic mix of ECE centre. Children attending ECE centres with a middle class/better maternally educated mix had greater gains for mathematics, literacy, and other cognitive outcomes, both short term and long term.
No effects of socioeconomic mix were found for dispositions in the English EPPE study, except for "Peer sociability" where children attending settings where a higher proportion of mothers had degrees, higher degrees, or other qualifications made less progress after taking account of prior social behavioural development. This contrasts with findings for cognitive outcomes, where gains are greater in such settings.
Aspects of ECE that can affect ECE impact
Longer duration of ECE experience is linked with cognitive ("academic") gains for children from all family socioeconomic backgrounds. Benefits of longer duration diminish over time, but may still be evident for mathematics and other schooling outcomes. High-quality ECE with longer duration has the strongest effects. An early starting age before age 3 is associated with gains, but there is mixed evidence about whether starting before age 2 is more advantageous than starting between age 2 and 3.
With respect to learning dispositions, longer duration and an early starting age in good quality ECE centres is beneficial, but longer duration in centres rated low-quality in terms of structural features (especially teacher qualifications) and adult–child interactions and communication is not.
A small number of international studies found an early starting age before age 2 or 3 is associated with higher levels of antisocial or worried behaviour at the time of attendance or shortly after school entry. These associations were generally found in centres rated as low-quality, suggesting it is early entry combined with poor quality that contributes to negative impacts. Where included in the analysis, frequent change of care was associated with antisocial behaviour.
Hours per week
Full-time attendance has no benefits for cognitive outcomes over part-time attendance in studies of children from a range of socioeconomic backgrounds. Some U.S. studies found children from low-income homes attending good quality ECE services gained more from full-time attendance (more than 30 hours) in literacy, mathematics, and other cognitive outcomes than those with part-time attendance.
U.S. studies report more hours (more than 30) of non-maternal child care (including care by relatives, not simply ECE) per week is associated with moderately more antisocial/aggressive behaviour at the time of attendance or shortly after school entry. Studies following children for longer periods do not report such findings.
Good quality ECE is the key to achieving gains on all outcomes measured. Aspects of adult–child interaction and opportunities afforded by the environment are associated with greater gains for cognitive outcomes and learning dispositions, and with lower levels of antisocial/worried behaviour. Aspects that are particularly important for outcomes are:
- the quality of staff–child interaction;
- the learning resources available;
- programmes that engage children; and
- a supportive environment for children to work together
The English EPPE study showed that "sustained shared thinking", associated with better cognitive achievement was more likely to occur with adults working 1:1 with children, and during focused small group work. Qualified staff working with children and low ratios of children to teachers linked to better gains for children, although these variables were confounded in some studies. (ECE centres that provide qualified staff may have high ratios of children to staff and vice versa.)
There were greater cognitive and learning disposition gains for children, and reduced antisocial/worried behaviour, in centres that encouraged parents to be engaged in their children's learning, with a focus on educational aims.
With respect to reducing problem behaviour and increasing levels of sociability, the closeness and quality of relationships between teachers and children was of core importance. Staff showing respect to children, listening to what they say, responding sympathetically, and using language and reasoning were associated with better social-emotional outcomes. The EPPE study also found better physical environment and space was associated with decreased antisocial and worried behaviours.
U.S. programmes catering for infants and toddlers and offering good quality centre-based ECE along with a range of family support services (health, community connections, parenting) were linked to positive outcomes for children (cognitive, learning dispositions, and social) and positive parent-child interactions.
Outcomes for parents
Positive outcomes for parenting (improved interactions with child, home environment and help for the child to learn at home, father involvement in parenting, parental knowledge of child learning, development, and behaviour) have been found in parent/whānau-led ECE centres where parent training and involvement in the education programme are core elements in programmes combining good quality ECE with parent education/support (integrated centres), and teacher-led centres where teachers have encouraged parents to work with them on educational aims. Specific efforts were taken in some programmes for teachers to work with hard to reach families, linguistic minority families, and teenage parents by providing interesting and accessible documentation, and by tailoring communication to parent interests and understanding.
Parental life course outcomes
Gains for parents were reported as follows:
- learning and undertaking study through the ECE service for a qualification;
- making social networks, community and cultural connections;
- increasing confidence and self-esteem; and
- favourable impacts on parenting-related stress and family functioning
These parent life course outcomes were associated with parent participation in the ECE community, in the education programme, formal learning opportunities, and parents taking up positions of responsibility within the ECE centre. Parent/whānau-led centres and integrated centres (centres that combine ECE and family support) seemed to offer wide opportunities for parents to enrich their lives.
Policy changes in Quebec and Argentina that both increased ECE supply and reduced its costs contributed to increased maternal employment as measured by the percentage of mothers in paid employment. The rate of increases in maternal employment was lower than the rate of expansion of ECE places. Where one kind of ECE only is expanded, that may influence decisions about hours of employment, e.g. expansion of full-time ECE provision was associated with full-time employment increases in Quebec.
Studies estimating probabilities of being employed or on welfare in relation to changes in child care costs and subsidies indicate that decreasing ECE costs is one factor that contributes to increased employment of low-income mothers. The decrease in costs has to be sizeable to make a marked difference to maternal employment. Availability of ECE, whether the mother has previous work experience or higher education levels, employment conditions and rates of pay, and availability of paid parental leave are other factors in maternal employment decisions.
International evidence demonstrates that investing in good quality ECE can bring cost savings and benefits to governments and economies as well as to children and families. Although cost benefit analyses measure only some quantifiable outcomes, these find that through provision of good quality ECE services, employment and tax revenues are increased, and savings are generated in educational and social expenditure.
Economists have cautioned that social, economic, and school policies also affect ECE cost benefit returns.
Good quality ECE has greater benefits for children from low socioeconomic families, but children from middle and high socioeconomic families also gain, as our earlier chapters have demonstrated. Economists, using conservative estimates of benefits based on recent relevant research evidence of ECE effects for children from across the socio-economic spectrum, have projected cost benefits of offering universal high-quality ECE for 2-, 3- and/or 4-year-olds. Most of the economic evaluations of ECE programmes have shown that benefits of public spending exceed the costs. Gains are not realised, or are not as great, if the ECE is of poor quality. Without considering the opportunity costs of that spending, comparing the investment to other types of early years intervention or alternative policy options, these evaluation findings tend to suggest that public spending for ECE programmes will result in good returns in terms of maternal employment, higher levels of the participant's lifetime earnings, reductions in usage of special education services, lesser criminal activity, and reduced use of social services that are expected to have a flow-on effect to the economy.
In summary, the existing research base shows positive outcomes (cognitive, learning dispositions, and social-emotional) of ECE participation for learners in the short and long term. These were most evident in centres rated as good quality in respect to responsive and stimulating adult–child interactions and rich learning environments, and in centres employing qualified teachers, with adult: child ratios and group sizes that enabled teachers to work with small groups of children or interact one on one with individual children.
Negative associations with aggression, antisocial behaviour, and anxiety in the short term found in mainly U.S. studies are linked to an early starting age, long hours in centres rated as low-quality, and frequent changes in child care. Weak evidence that ECE may be associated with higher rates of infections and cortisol levels (where centres were low-quality) was found.
ECE participation can enable parents to learn more about parenting, develop social and community networks, and build greater confidence; and participate in paid employment. These gains can be thought of as empowering. They also interact with those found for children, and each contributes to family and societal functioning.
A number of studies showed that investing in universally available good quality ECE can bring benefits to governments, as well as to children and families.
The diagram below illustrates conditions that support the teaching and learning that in turn directly contributes to good quality outcomes for children and parents. The early childhood services that contribute to positive child and family outcomes are settings characterised by:
- intentional teaching;2
- family engagement with ECE teachers and programmes, where social/cultural capital and interests from home are included, and both family and teachers can best support the child's learning; and
- a complex curriculum involving both cognitive and non-cognitive dimensions.
Participation in teaching and learning in effective ECE settings is not dominated by teachers, but shared with families and children. Children are active in their own learning and contribute to the learning of others, rather than simply being seen as the effect of inputs or external forces, or reacting to their current main contexts. Hence the reverse arrows in the diagram showing linkages from child outcomes back to the ECE setting.
Facilitating environments provide conditions for the kind of teaching and learning that lead to quality outcomes for children, especially qualified staff, low child: adult ratios, small group size, and staff professional development opportunities. Qualified teachers are likely to draw on their knowledge and experience of children and pedagogy to offer the kinds of cognitively challenging adult–child interactions that are linked with gains for children. The NICHD ECCRN (The National Institute for Child Health and Human Development Early Child Care Research Network) study (2002) using structural equation modelling, found a mediated path from structural indicators of quality (teacher qualifications and staff: child ratios) through process quality to cognitive competence and caregiver ratings of social competence. These authors suggest that "more caregiver training may lead to better interactions between children and adults, while lower ratios may lead to more interactions" (NICHD ECCRN, 2002, p. 206).
Diagram 1: Conditions, interactions, and outcomes for children and families
Government policies for education, health, housing, welfare, and employment also influence the wellbeing and support of families, and opportunities for parent employment and development. Employment policies, including paid parental leave, influence the ability of parents to participate in paid employment and balance employment with family life. Several studies have emphasised the value for parents and children of extensive paid parental leave (12 months or more) from the child's birth. Our review has highlighted that returns from early investment in ECE are high, but good quality schooling is important in sustaining gains from ECE participation.
The kinds of institutional, funding, and regulatory arrangements that support provision of good quality ECE will enable these features to be achieved, e.g. through regulating recommended standards for staffing (qualifications, ratios, and group size), opportunities for professional development for all teachers, opportunities for teachers to investigate teaching, learning using inquiry approaches (Mitchell & Cubey, 2003), and support for good quality provision to be available in all communities. This review gives substantial support for continuing to give good quality ECE priority in New Zealand's efforts to improve outcomes for children.