Outcomes of Early Childhood Education: Literature Review

2. Children: Cognitive outcomes

“Cognitive” outcomes are the focus of much of the research on the impact of ECE. Cognitive outcomes were mainly defined as “academic knowledge” based on traditional academic subjects, or ability as measured by IQ tests or developmental quotients. Measures used were achievement tests or teacher assessments of school performance, particularly in mathematics, reading, and literacy; IQ; school readiness; grade retention; and special education placement. These outcomes are reported separately in many studies and in this chapter, but they are also linked to learning dispositions and social-emotional outcomes. Indeed, the longitudinal case studies of practice in the English EPPE study of over 3000 children and 141 centres found “The settings that viewed cognitive and social development [including learning dispositions] as complementary seemed to achieve the best outcomes” (Siraj-Blatchford et al., 2003, p. vii).

In this and subsequent chapters we move on from our review of pre 1995 studies in Chapter 1, to examine research reports from 1995 onwards. The studies used are four U.S. intervention studies chosen because they followed children long term (the Abecedarian study, the High/Scope Perry Preschool study, the Chicago Child–Parent Centre study, and the Infant Health and Development Program study), studied general everyday ECE experiences, and studies using national survey data.

In this section, we have mapped out the size of results for cognitive outcomes, highlighted consistencies and differences across studies, and then analysed differences associated with child and ECE characteristics. Effect sizes are reported after taking account of background variables unless stated otherwise.

Mathematics

In all, 26 studies  reported on mathematics outcomes from ECE participation. Those that provided greatest insight for our research questions examined quality of ECE, types of ECE, stability, timing and duration of ECE, and characteristics of children.

Most studies comparing children who participated in ECE with those who did not, found positive gains from ECE participation for mathematics at the time of attendance and in the early years of schooling. In general, the intervention studies reported medium to large effect sizes at age 8, and the general studies reported small to medium effect sizes. All six studies measuring long-term effects of ECE participation found benefits for children continuing at least until at ages 15–16.

One study found negative impact of centre-based ECE for children from low-income families, but positive impact for children from high-income families.

Three studies found no impact of ECE on mathematics outcomes.  

Positive outcomes

Short-term gains

Intervention studies: Studies of the Abecedarian, Chicago Child–Parent Centre and Perry Preschool programmes  reported medium to large effect sizes at age 8 (d=0.29–0.81), for the full intervention versus none. The Infant Health and Development Programme, which did not find benefits overall, did find benefits for the heavier but not the lighter birth-weight premature children at age 8. The authors suggest the lighter birth-weight children may have needed continued support (the intervention finished at age 3), or may have included more neurologically impaired children who could not benefit from the intervention.

General studies: U.S. studies, the English EPPE study and Northern Ireland EPPNI study that followed children through from ECE programmes to the third year of school  reported small to medium effect sizes (d=0.07–0.43), with most in the range d=0.23–0.29. Many of these are U.S. studies. The lowest effect sizes were in Gilliam and Zigler’s (2004) summary of U.S. pre-K evaluations in the U.S. (using comparisons with national norms or comparison groups who may or may not have attended ECE), and a study of an entire kindergarten cohort in a large urban U.S. setting (Fantuzzo et al.., 2005), comparing those with centre-based ECE with those who had experienced informal care or no extra care. For example, in the pre-K evaluations, small effect sizes reported for South Carolina first grade and Texas 3rd grade ranged from d=0.07 to .09. Michigan reported an increase of 16 percent more students passing the Michigan Educational Assessment Mathematics test at fourth grade. The highest effect sizes were medium, and were found in the EPPE study (d=0.43) and Oklahoma’s pre-K programme  (d=0.38) at school entry. In Oklahoma, some structural features of quality, i.e. teacher qualification requirements and pay rates, tend to be higher than in other states.

The EPPE study reported reducing effect sizes on early number from d=0.43 at school entry, to d=0.38 at age 6, and d=0.2 at age 7.

Studies using national survey data: Studies using U.S. national survey data  reported small positive effect sizes in the first year of school (d=0.10 to 0.19). In Argentina, Berlinski, Galiani, and Gertler (2006) found positive impacts of pre-primary education on third grade standardised mathematics tests, following Argentina’s expansion of universal pre-primary education between 1993 and 1999. They estimated one year of preschooling increased average third grade performance in mathematics (and Spanish) by 8 percent of a mean of 61.4 or by 23 percent of the standard deviation of the distribution of test scores. The Argentina preschools offered a curriculum aimed at developing personal autonomy and behavioural skills, social skills, logical and mathematics skills, and emotional skills, and average class sizes of 25 students and two shifts (i.e. 50 children in total).

Long-term gains

Six studies reported long-term gains in mathematics performance, with effect sizes generally decreasing over time. The Competent Children, Competent Learners study, focusing on aspects of ECE quality, found advantages of some aspects of high-quality ECE at age 14 and age 16.

Intervention studies: The Abecedarian project found medium effect sizes for mathematics of d=0.45 at age 8, d=0.35 at age 12, and d=0.44 at age 15. The Chicago Child Parent-Centre programme found smaller effect sizes of d=0.32 at third grade, d=0.24 at fifth grade, and d=0.19 at eighth grade (Karoly et al.., 2005). Both programmes combined parent education with good quality ECE, but the Abecedarian programme began in the child’s first three months and the Chicago Child Parent-Centre programme at ages 3–4.

General studies: The Competent Children, Competent Learners study found modest contributions from early childhood education to age-14 and age-16 mathematics scores, with ECE quality variables and length of experience accounting for 2.5–5 percent of the variance in age-14 mathematics scores, and an ECE quality variable (ECE staff guiding the children) accounting for 4 percent of the variance in age-16 mathematics scores.

Two of the evaluations of pre-K summarised by Gilliam and Zigler (2004) measured long-term impacts. New York-EPK found significant positive impacts in mathematics at 6th grade. In Maryland there were statistically significant effects of pre-K participation on mathematics in 5th, 8th, 9th and 10th grades.

Studies using national survey data: Goodman and Sianesi, (2005), using British National Child Development Survey data found a small average gain for those who had attended ECE in mathematics tests of d=0.08 effect size at age 7, reducing steadily to d=0.05 effect size (not significant) at age 16.

Results for age-15 mathematics performance in the recent international PISA study showed students who had attended ECE for at least a year before school scored 8 points higher on average than those who had not, after taking socioeconomic background into account (OECD, 2004).

No impact

No ECE impact for mathematics was reported in three U.S. studies with children from low-income homes. Two found no gain for mathematics for children who had experienced Head Start, compared with their peers, at ages 3–4 (U.S. Dept. of Health and Human Services, 2005), and ages 12–17 (Aughinbaugh, 2001). However, it is not clear how different the two groups were, since the non-Head Start group included some who had other ECE experience. One study comparing differences within everyday ECE experience of quality and type found that those who attended comparatively higher-quality ECE had much the same mathematics scores as those who attended lower quality (Votruba-Drzal, Coley & Chase-Lansdale, 2004). However, in this study, most of the ECE settings were minimally adequate in meeting basic developmental needs, even those that were of higher-quality.

Currie and Thomas (2000) have shown that poor school quality can undermine early gains. Another explanation for why the Auginbaugh study did not show long-term gains for Head Start children is that they may have gone on to attend poor quality schools with disadvantaged peers. Votruba-Drzal et al. suggest reasons why their findings differ from other studies are that within the normative range of child care quality available to low-income children in their communities, the sample children may need higher-quality ECE than was found in the study. Even relatively high-quality child care may not be able to make up for other environmental challenges. These children may also need consistently high-quality experience over a longer period to gain cognitively. The study did not collect data on length of ECE experience, and the authors noted other studies, e.g., the NICHD study, showing gains for cognitive performance related to ECE length. The data used was only a snapshot of children’s child care experiences.

Mixed impact

One U.S. study using national survey data (Gamoran et al.., 1999) found that children from low-income homes who participated in centre-based care did less well on tests of mathematics, and high-income children did better, than similar children at age 6 who did not participate in this type of care, but could have been in non-maternal home-based or maternal care. Their study included only children with siblings and did not analyse centre care quality or duration. Burchinal and Nelson (2000) have summarised U.S. studies showing that children from more advantaged families tend to attend higher-quality child care than children from less advantaged families. Such selection factors could account for this study’s findings. As well, a hierarchical model rather than the fixed effect model used may have been a more appropriate analysis for this data.

Differences for population groups

Gains in mathematics, from ECE participation were found for children across the board. However, there are also additional gains for children from low socioeconomic homes.

Low income: The Competent Children, Competent Learners study found an indication that children who had been in very low-income homes at age-5 appeared to benefit at age 14 more than most others in cognitive competencies, including mathematics, if their final ECE centre had been of the highest quality in terms of staff guidance.

In Argentina, Berlinski, Galiani, and Gertler (2006) found bigger gains for children living in poverty. While all children benefited, their gain was 1.6 points higher in mathematics at 3rd grade than the gain of children who were at the country median level of poverty. The curriculum in Argentina was designed to develop communication skills, personal autonomy and behavioural skills, logical and mathematical skills, and emotional skills.

In the U.S., implementation of a conceptually broad mathematics curriculum, involving teachers in professional development and parents having support for learning at home, was associated with benefits for all children. Benefits were greater for children from low-income families (low-income intervention versus comparison group d=0.931; middle-income group versus comparison d=0.723). The rate of change was greater for children from low-income families than for children from middle income families. Effect sizes for change from fall to spring for the low-income group were d>2.0, and for the middle income group d>1.5.

Maternal education: The U.S. Cost, Quality and Outcomes study found the effect of high-quality child care for mathematics skills was greater for children whose mothers had less education than for children whose mothers had more education.
Ethnicity: The EPPE study reported that children from some ethnic minority groups (including Black Caribbean and Black African) made greater progress in early number concepts during preschool than white U.K. children or those for whom English was a first language, after taking account of background characteristics. These groups overall had significantly lower cognitive scores at entry to the study in language measures but not nonverbal measures. Sylva et al. (2004) suggest preschool provision may provide opportunity for such children to catch up.

Gender: Most studies found no gender differences in gains. However, in the EPPE study,  boys gained more than girls for early number concepts if they attended higher-quality centres. The home learning environment scores (measured by parent reports of activities such as reading to the child, playing with letters and numbers, painting and drawing, going to the library) were also lower than for girls, so boys may have been gaining less from home. The study found the home learning environment exerted a significant and independent influence on attainment both at age 3 and the start of primary school. The gains being made by boys from ECE participation were therefore particularly important.

Birth weight: The U.S. Infant Health and Development study  reported positive outcomes for the heavier birth weight intervention group during preschool attendance and to age 8 compared with a matched group that did not receive the intervention, but there were no differences in mathematics measures for the lighter birth weight intervention group. The authors suggested the lighter birth weight group may have included a higher proportion of neurologically impaired children who could not benefit from the intervention, who may have needed a more structured and professionally designed home environment, or may have needed continued support beyond the three years of the intervention.

Duration

All four studies examining the impact of length of ECE participation and one study on the intensity (hours per week) of ECE participation  found gains for mathematics from longer ECE experience. These lasted some time after the ECE experience finished.

Duration: The Competent Children, Competent Learners study found that the longer children had attended ECE, the higher their mathematics score at age 12. At age 14 this remained the case controlling for family income, with a significant contrast of around 15 percentage points between those who had attended for 48 months or more, and those who had not. The differences were reduced to the indicative level once maternal qualifications were taken into account. At age 16, though the trend was still evident, it was not statistically significant.

Longer duration in ECE was associated with more progress on number concepts at school entry in the EPPE study: The medium effect sizes increased with ECE duration. (<1 year: d=0.460; 1–2 years: d=0.440; 2–3 years: d=0.568; > 3 years: d=0.631).
One year or two years participation in ECE compared with no ECE participation was associated with development of mathematical competence just after kindergarten (first year of school in the U.S.) entry, with children attending for two years having slightly higher (not statistically significant) scores than those attending for one year in the Barnett and Lamy (2006) study of U.S. pre-K.

A Swedish study (Broberg, Wessels, Lamb and Hwang, 1997) reported higher scores for mathematical ability at age 8½ for children entering centre based care before the age of 40 months compared with those who started after 40 months.

Intensity: A U.S. randomised trial (Robin et al.., 2006) found children from low-income homes who had been assigned to an extended duration good quality ECE programme (8 hours for 45 weeks per year) improved by 12 standard score points on tests of mathematics skills, while children who had been assigned to participate in a 2½–3-hour programme for 41 weeks per year improved by 7 standard score points, in comparison with children cared for at home or in private care.

ECE centre peer group composition

Two studies have analysed ECE peer group composition in terms of likely advantages from socioeconomic mix, and found that higher socioeconomic mix does benefit children, over and above their own individual family characteristics. In the EPPE and EPPNI studies, children attending ECE centres with a higher proportion of children whose mothers had degrees, higher degrees, or other professional qualifications made more progress in early number concepts at school entry and age 8. The Competent Children, Competent Learners study reported that children whose final ECE centre served mainly middle-class families had higher scores for the cognitive competencies, including mathematics. These associations continued to be statistically significant at age 14 after taking into account family income and maternal qualification, but were not significant at age 16.

Quality

Process quality: Observed measures of the quality of experiences and interactions within the ECE setting have been found to be associated with mathematics development in three longitudinal studies, the Competent Children, Competent Learners study, the English EPPE and Northern Ireland EPPNI studies, and the U.S. Cost, Quality and Child Outcomes study.

The Competent Children, Competent Learners study found patterns of associations with mathematical competency scores and the following items to age 14:

• ECE staff responsiveness to children
• ECE staff guide children in the context of activities
  
• ECE staff ask open-ended questions
  
• Children can complete activities
  
• ECE staff join children in their play
• Provision of a print-saturated environment.
  

At age 16, some aspects of ECE centre quality were still having an impact over and above that of the equivalent age-5 competency, maternal qualifications, and age-5 family income: ECE staff guiding children accounted for just under 4 percent of the variation in age-16 scores.

In the EPPE study three caregiver interaction scales, which assess negative staff–child interactions (detachment, permissive, and punitive), showed a negative impact on early number concepts progress at the date of starting primary school. Conversely, scoring high on the “Positive relationships scale” was associated with more progress in early number.

Aspects of ECE programme focus had some association with later mathematics competency. Both the EPPE and EPPNI studies used the ECERS-E scale, designed to assess curricular provision in literacy, mathematics, science and environment, and diversity. Neither study found linkages between mathematical competence at age 6½ years and the mathematics subscale, but they found associations with other curriculum subscales. The EPPE study found a statistically significant association between early number concepts and high ratings on the diversity subscale, and a non-significant association with the literacy subscale. The diversity subscale is related to gender equity, multicultural education and “inclusive literacy”. The EPPNI study (Melhuish et al.., 2006) found that children who were in ECE centres rated higher on their provision of science attained better scores and made more progress in numeracy.

The Cost, Quality and Child Outcomes study found children in higher-quality care, with higher ratings on observed classroom practices, scored better in math skills after controlling for background variables, than those in lower-quality care. Effect sizes were small: Year 1 child care: d=0.29, Year 2 child care: d=0.28, kindergarten: d=0.20, 2nd grade: d=0.29.

Burchinal, Peisner-Feinberg et al. (2000) pooled data from the Cost, Quality, and Child Outcomes study, North Carolina Head Start Partnership study, and the Public Preschool Evaluation project. All these studies included the same measure of child care quality and family selection factors, and similar or the same measures of language and pre-academic development and social skills. In the short term, children in poor quality centres had significantly lower mathematics scores than those in high-quality (medium effect size d=0.48) and lower mathematics scores (not statistically significant, effect size d=0.33) than those in medium quality.

Structural quality: Structural aspects of staff: child ratios (more adults to children) and smaller group size were associated with enhanced mathematical abilities in a Swedish study (Broberg et al.., 1997) at age 8. Those in centre-based ECE did better than those in family day care.

Early et al. (2006) found teachers’ education (years of education, highest degree, and Bachelor’s degree versus no Bachelor’s degree) linked to gains on standardised measures of mathematics skills across the pre-K year. Children gained additional points where teachers had a Bachelor’s degree compared with less than a Bachelor’s degree. These associations were not found with language and early literacy. The authors suggested that because of a national focus in the U.S. on language and early literacy, it may be that teacher education programmes were preparing teacher trainees to work in that area, but were not specifically working with them on mathematical thinking.

In the EPPE study, higher levels of teacher qualifications were associated with positive aspects of adult–child interaction, which in turn benefited child outcomes, i.e. the linkage with outcomes was indirect through the association of qualifications with better quality ECE provision.

Curriculum: Starkey et al. (2004) examined the implementation of a conceptually broad mathematics pre-kindergarten curriculum, in which teachers undertook professional development and changed their curriculum, and parents were offered materials and curriculum guide sheets and classes to help them support mathematics learning at home. Over the period of a year, intervention children in comparison with control children gained significantly enhanced mathematical knowledge (low-income intervention versus comparison group d=0.931; middle-income group versus comparison d=0.723).¹

Footnotes

1. A New Zealand study (Young-Loveridge, Carr, & Peters, 1995) also showed how professional development with teachers focused on mathematics contributed to enhanced mathematical experiences and resources within the ECE centres.