Outcomes of early childhood education: Literature review

Publication Details

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

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Chapter 8: Conclusion

What answers do we have now in response to the four large research questions underpinning this review of research on the impact of ECE?

What (short-term and long-term) developmental, educational, social, and economic outcomes are associated with participation in ECE for learners and their families?


The existing research base as a whole shows positive outcomes for learners, with a small number of studies showing some neutral effects, and an even smaller number of studies showing negative effects or positive outcomes for ECE associated with participation in quality programmes.

Most of the research to date on outcomes for children has focused on cognitive and social-emotional aspects, with only a small number collecting more than general information about health. There is little yet specifically on the learning dispositions and key competencies identified as important for learning in the 21st century, and included in Te Whāriki and the draft New Zealand school curriculum, although some of the research more traditionally framed has relevance to these outcomes.

Outcomes for learners

ECE experiences are generally associated with positive outcomes for children in both the short and long term for mathematics, reading, and general cognitive or school performance. Effects are usually more marked in the short term.

They are generally associated with positive outcomes for children in both the short and long term for learning dispositions and social-emotional wellbeing. Again, the short-term positive effects are more marked than the long-term. However, there are some studies that find associations in the short term with increases in the small proportions of children who are at the extremes for aggression, antisocial behaviour, or anxiety. These associations do not appear to persist in the long term, though the NICHD study showed some poorer social skills and poorer work habits related to longer hours at ECE (intensity) lasting until about age 8. The EPPE study found high-quality ECE after the age of 3 can have a positive impact in reducing antisocial behaviour associated with long hours and an early age of entry into centre-based ECE.

The picture in relation to health outcomes is less solid than the aspects of cognitive and learning dispositions. Where there is information about infections, it seems that they can increase in children in the short term; the information about cortisol levels suggests these may be higher, but the effect of this is not as clear as, say, the picture from the research on cognitive outcomes. We found no analysis of long-term health outcomes.

Outcomes for parents

Research on outcomes for parents generally shows positive short-term outcomes for parenting and parent life course outcomes (studying for a qualification, making social connections, increasing confidence, and reducing stress), and for maternal employment. We found no long-term studies of outcomes for parents.

Cost benefits to government

A small number of studies showed that investing in good quality ECE can bring actual cost benefits to governments, as well as to children and families. These may arise through increased tax revenues from parental take-up of employment while the child attends ECE, and savings generated in educational, welfare, and justice expenditure. The evidence of larger effect sizes for children's outcomes from very good quality ECE indicates greater returns will be likely from investing in high-quality ECE. All children benefit from such provision.

Are different outcomes associated with different population groups and under different
circumstances/contexts?

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?


On the whole, positive ECE outcomes are not confined to particular population groups. Positive outcomes are supported by the provision of ECE of sufficient quality to complement home and other experiences, or, in the case of children from impoverished homes, to strongly augment their learning opportunities and social support. The few studies that have included peer socioeconomic mix as one of the ECE variables analysed have found that it is preferable not to segregate low-income children—that (as in schools), children benefit from peer mixes that contain well-nourished human capital.

There is some indication that cognitive gains from good quality ECE may be greater for children from low-income homes than for children from higher-income homes (although all benefit), and that children for whom English is an additional language may make faster progress on early mathematics and literacy measures during ECE attendance. ECE attendance may help them to "catch up" with peers.

There is some indication from the research—but without clear specification—that longer ECE experience is beneficial for cognitive outcomes and learning dispositions. There is little indication that one particular kind of ECE (e.g. full-day or part-day), is better for children's outcomes in all contexts.

The quality of their ECE setting is central to ECE's contribution to positive outcomes for children. What seems to matter for positive outcomes for children is:  

  • the quality of staff–child interaction;
  • the learning resources available;
  • programmes that engage children; and
  • a supportive environment for children to work together.

We explore how these aspects of quality matter in the next section.

Interaction or Process Quality:

Positive effects of ECE participation were found in settings described as good quality in terms of adult–child interactions that are responsive, cognitively challenging, and encourage joint attention and negotiation. In higher-quality ECE settings, adults offer learning environments where there is opportunity for dialogue and use of complex language, children may choose activity levels that are suitable and engaging, children are encouraged to problem solve, and adult–child interactions involve sustained shared thinking and open-ended questions to extend thinking.

Educational Curriculum:

There is evidence that a curriculum where children can investigate and think for themselves is associated with better cognitive performance in later schooling than one that is academically oriented. Providing differentiated learning opportunities that meet the needs of individuals and groups, and staff who view cognitive and social development as complementary and do not prioritise one over the other, were features of effective settings in the large-scale English EPPE study. Studies suggest greater distribution of power or responsibility to children, and engagement of families focused on pedagogical outcomes are factors supporting learning dispositions and social competence.

Structural Quality:

Structural quality refers to the structures needed to support good quality in early childhood education programmes. Significant associations were found between teacher qualifications and education, and child outcomes. Qualified and educated teachers use more words and more complex language when communicating with children, and use more sustained shared thinking episodes that are associated with positive outcomes.

Higher staff to Child Ratios:

Higher staff child ratios (i.e. more staff to children), where measured, were associated with positive outcomes in some studies. Where an association was not found, ratios were confounded with teacher qualifications. Good adult: child ratios are important in enabling teachers to be responsive, and scaffold and stimulate learning. Ratios were found to be especially important for language stimulation of babies and toddlers.

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 study 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. The 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).

Group size was not measured in most studies, but less time (but not small group size) spent in whole-group activities was associated with better age-7 cognitive performance in analysis of the IEA Pre-primary Project. It may be that how children are grouped within settings, rather than overall centre size, is what counts for quality. The English EPPE study showed more "sustained shared thinking" which is associated with better cognitive achievement was more likely to occur with adults working 1:1 with children and during focused small group work.

Recommendations for child care standards for qualifications, ratios, and group size in the U.S. and associated in the NICHD study with better child outcomes were:

  • Qualifications: ECE teacher qualifications
  • Ratios: 1:3 at 6 and 15 months; 1:4 at 24 months; 1:7 at 36 months.
  • Group size: 6 at 6 and 15 months, 8 at 24 months, 14 at 36 months.

ECE services for babies and toddlers need to be of the highest quality, given the fast rate of development occurring then, and the findings that an early age of entry into low-quality ECE centres is detrimental to social-emotional outcomes. The recent OECD report examining ECE policy issues in 20 OECD countries argues for provision of extensive paid parental leave in the first year, alongside high-quality ECE:

The provision of remunerated parental leave of about a year, followed by a child's entitlement to place in an early childhood service, allows parents to be with their child in the critical first year, supports the family budget and also facilitates the return to employment. This is a human support to family life and bonding that advanced industrial economies should consider (OECD, 2006, p. 207).


In the Nordic countries generous parental leave provisions are an alternative to infant ECE programmes, and babies in the first year are almost always at home.

Relationships with Parents:

All studies using statistical analysis controlled for home background variables. The EPPE study found that engaging parents in ongoing assessment of children's learning and sharing educational aims with parents could help improve the home learning environment and reinforce learning between home and the ECE service. This is a potentially powerful role for ECE services. There is some limited evidence that provision of good quality integrated ECE centres offering extended services to children and families is associated with positive learning dispositions and social-emotional outcomes. Perhaps the connection made with families through this type of service provision enables greater sharing of information and feedback.

Professional Development:

Professional development can make a valuable contribution to enhancing the kinds of interactions and curriculum knowledge that are associated with effective pedagogy and outcomes for children (Mitchell & Cubey, 2003). Siraj-Blatchford (2004) highlights the importance of professional development for developing and monitoring provision for diversity and encouraging development of parental partnerships focused on children's learning, which were associated in the EPPE project with achievement for all children. The research being undertaken by New Zealand's Centres of Innovation (COI) and the Teaching Learning and Research Initiative projects offer examples of how ECE centres in New Zealand have approached building up teaching and learning processes that are associated with positive outcomes. Reports from the first round of COIs (such as Roskill South Kindergarten's (Ramsey et al., 2006), which illustrates an interweaving of dispositions and cognitive outcomes and approaches to enhancing family participation and child outcomes consistent with the national curriculum, Te Whāriki) show how practices can be lifted and children extended through teachers engaging in critical, reflective investigation, and acting on their findings. Opportunities for such investigation can be supported through institutional frameworks and could be the focus of policy that ensures they are available for all practitioners.

We envisage outcomes, context, and pedagogy as contributing to and reinforcing each other. Children also negotiate their own learning pathway and contribute to the environments and learning of others.

Institutional, funding, and regulatory frameworks

Extrapolating from this, 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 ensuring recommended standards for staffing (qualifications, ratios, and group size), opportunities for professional development for all teachers, support for good quality provision to be available in all communities, and opportunities for teachers to engage in critical reflective investigation of pedagogy consistent with the national curriculum, Te Whāriki. Thus, the test of any framework should be whether it provides sufficient incentives and support for these aspects of quality to be included in every ECE setting.

If one wants the outcomes to be distributed fairly, then such frameworks also need to focus on ensuring sufficient provision of quality ECE in all communities. The need is greatest in low-income communities.

As yet, there is no systematic research comparing different configurations of quality provision across countries in relation to children's outcomes. Such (expensive) research might be able to provide more understanding of how different policy frameworks support quality and positive outcomes for children, but there would be difficult questions of comparable measures of outcomes.

Adverse outcomes from ECE are rare in the research literature. They are more likely where ECE quality is poor, with suggestions that intensity of ECE experience (long hours each week) and early starting age may have negative short-term outcomes for antisocial and worried behaviour, for children in everyday ECE—but not for low-income children in "intervention" ECE, where good quality staffing standards, parent support, and education are features. The findings for early starting age highlight the importance of centres catering for babies and toddlers meeting recommended standards for quality. The evidence so far is unclear whether these adverse outcomes persist.

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?


The Competent Children, Competent Learners study shows how cognitive and social-emotional performance is related, while also being distinct (Wylie et al., 2006). We learn within social settings, often through our interaction with others, both adults and peers: each kind of competency supports the other. Most studies of the impact of ECE do not portray it as producing one kind of outcome at the expense of another.

Outcomes are sensitive to context, so that parallel or successive contexts, such as schooling, may build on or overshadow competencies developed during ECE experiences. Positive identities as learners are able to support further learning. Cunha et al.'s (2005) formal model of the economics of investing in human capital describes two mechanisms: self-productivity and complementarity, which explain how "skills beget skills". Self-productivity says that skills that develop in one period persist into future periods; skills are self-reinforcing. "For example, self-control and emotional security may reinforce intellectual curiosity and promote more vigorous learning of cognitive skills" (p. 5). So early skills may change their character but still be part of an educational pathway. Also "Students with greater early cognitive and non-cognitive abilities are more efficient in later learning of both cognitive and non-cognitive skills. Thus the enriched early environments of the Abecedarian, Perry and CPC programs promote greater efficiency in learning in high schools and reduce problem behaviours" (p. 65). Complementarity implies that early investment has to be followed up by later investment in order for the early investment to be productive. Facilitating environments have to follow facilitating environments.

Cunha et al.'s model also emphasises the role of non-cognitive skills: ("Non-cognitive skills (perseverance, motivation, self-control and the like) have direct effects on wages (given schooling), schooling, teenage pregnancy, smoking, crime, and achievement tests" p. 85.) The model emphasises the contribution of family environments.

Where the size of the contribution of ECE to outcomes for children has been statistically assessed, it is strongest for the cognitive areas. In the studies reviewed here, it ranges from 0.02–0.28 for reading, and 0.10–0.23 for mathematics in analyses of the contribution of everyday ECE centres serving a range of populations; it is much higher for the well-resourced intervention studies, serving children from low-income homes, ranging from 0.32 to 0.81 for mathematics in the short term, and 0.19 to 0.44 in the long term, and for reading, from 0.34 to 0.89, and 0.17 to 0.44 in the long term. The differences in ranges is related to the kind of provision, but effect sizes also reflect the size of a study sample, and the difference between groups being compared, as well as how variables were measured and specified, and the richness of datasets available.

But overall, these effect sizes are indicating that ECE can make a real contribution to the development of mathematics and reading, in both the short and long term.

There are similar trends in relation to more generally measured cognitive and school performance outcomes, though these tend to be measured more in intervention studies designed to support low-income children.

There is more variation in effect sizes for social-emotional outcomes: somewhat lower than the cognitive outcomes for everyday ECE for social skills and social-emotional wellbeing, sizeable (even if for small proportions of children) for the studies finding short-term negative impacts for antisocial, anxious, or aggressive behaviour, but equally strong for the longitudinal intervention studies, where these are gauged in terms of persistence and avoidance of crime.

One indication of how these long-term intervention findings may translate into "ordinary" terms is Karoly et al.'s (2005) estimate of the California state fiscal benefit from providing universal ECE for 1–2 years before school entry, at about 23 percent of the level in the Chicago Parent–Child programme. This estimation was related to expected increases in student years of education, and decreases in grade retention, use of special education (number of students and years), secondary school dropouts, decreases in the number of children abused or neglected, and decreases for court cases involving juveniles. No New Zealand study has collected this kind of data to allow a similar estimate, and differences in systems, e.g. identification of special education needs and funding for moderate- and low-needs students would mean that the estimate for New Zealand might be different. However, the salient point here is the difference in the size of the impact between expensive targeted interventions, and everyday universal provision.

We cannot estimate a range of effect sizes for health, or for parenting outcomes.

ECE contribution to maternal employment shows a range of an increase of 7 to 14 percent from "natural experiments" that increased provision and affordability, and these increases as a proportion of the increase in ECE places ranged from about a third to almost 100 percent: indicating the role of other factors in deciding when mothers take on paid employment. Analysis focused on changes to child care costs, mainly for low-income mothers, shows a greater range of variability, some linked to the kind of ECE made available (and how available it was), and some to maternal experiences and attributes. But, on the whole, ECE's contribution to maternal employment is notable.

Most children in New Zealand now have some ECE experience, but other experiences, particularly home, strongly influence children's learning and development. ECE has become part of the tapestry of growing up in most Western countries. When compared with the contribution to children's development and wellbeing of family income levels (or rather, poverty), or the human capital from their parents' education, the size of the ECE contribution is much smaller: usually around a third to a half at most. But countering the trend for income disparities to widen, or making a large shift in parental human capital, is a much harder policy and practical task than improving the provision of good quality ECE. The review provides substantial support for continuing to give good quality ECE priority in New Zealand's efforts to improve outcomes for our children.

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