Technical Appendix


“Earlier starting age” refers to increasing the time a child spends in early years education by beginning at a younger age. This would typically mean being enrolled in nursery or pre-school from the age of two or three and experiencing up to two years of early years education before starting school.

For an assessment of the evidence related to increasing the number of hours spent in early years education at a given time, see “Extra hours”.

Search Terms: pre-primary, pre-school, early childhood settings, early childhood education, pre-K, pre-school education, prekindergarten, early starting age

Evidence Rating

There are three meta-analyses suggesting a positive impact on learning outcomes. Two of these include experimental and quasi-experimental studies and explore some aspects of variation in impact. There are some indications that the impact of high-quality early years provision is particularly positive for children from low-income families.

Evidence about the medium- and long-term impact of an earlier starting age is mixed. In some studies some improvements are detectable into primary school. However, in several US studies benefits do not appear to be sustained. It appears likely that the quality of provision is the key determinant of sustained improvement, but more evidence is needed in this area. In the UK, the highest quality study conducted to date which has assessed the impact on an earlier starting age is the Effective Provision of Pre-school Education (EPPE) project. The study looked at the association between different kinds of pre-school provision and young children’s learning, and involved 3,000 children. However, its correlational design means that it cannot rule out some alternative explanations for its finding that earlier starting ages boost learning outcomes. In general effects tend to be higher the nearer they are measured to the age of starting school. Some studies find effects persist throughout school.

The school starting age is different in different countries, which can also make it hard to assess the applicability of evidence from overseas. For example, though findings related to earlier starting ages from the USA are consistent with those from the UK, pre-kindergarten education in the USA typically involves four and five year olds, and fewer high-quality studies have assessed the impact of starting at two or three. Overall the evidence is rated as moderate.

Additional Cost Information

Overall, the costs are estimated as very high. A full time pre-school place costs about £8,000 for 40 weeks at about £200 per week for a private provider. A maintained nursery place for 3-4 year olds costs about £4.25 an hour or £6,400 per year.


Barnett, W. S.
Effectiveness of early educational intervention open_in_new
Science, 333(6045), 975-978
Berlinski, S., Galiani, S., & Gertler, P.
The effect of pre-primary education on primary school performance open_in_new
Journal of Public Economics, 93(1), 219-234
Camilli, G., Vargas, S., Ryan, S., & Barnett, W. S. (Abstract arrow_downward)
Meta-analysis of the effects of early education interventions on cognitive and social development open_in_new
Teachers College Record, 112(3), 579-620
Cattan, S., Crawford, C., & Dearden, L.
The economic effects of pre-school education and quality open_in_new
London: Institute for Fiscal Studies (Report 99)
Gormley Jr, W. T., Gayer, T., Phillips, D., & Dawson, B.
The effects of universal pre-K on cognitive development open_in_new
Developmental psychology, 41(6), 872
Melhuish, E., Quinn, L., Sylva, K., Sammons, P., Siraj-Blatchford, I., & Taggart, B.
Preschool affects longer term literacy and numeracy: results from a general population longitudinal study in Northern Ireland open_in_new
School Effectiveness and School Improvement, 24(2), 234-250
Melhuish, E., Taggart, B., Siraj-Blatchford, I., & Sammons, P.
The effective pre-school provision in Northern Ireland (eppni) project: summary report 1998-2004 open_in_new
Bangor, Co. Down: The Department of Education, NI.
Sylva, K. (Ed.). Melhuish, E., Sammons, P., Siraj-Blatchford, I., & Taggart, B.
Early Childhood Matters: Evidence from the Effective Pre-school and Primary Education Project open_in_new
London Taylor & Francis
Sylva, K., Melhuish, E., Sammons, P., Siraj, I. and Taggart, B.
Students’ Educational and Developmental Outcomes at Age 16 open_in_new
Effective Pre-School, Primary and Secondary Education 3-16 Project (EPPSE 3-16), DfE Research Report no. DFE-RR354, London: Department for Education
Sylva, K., Melhuish, E., Sammons, P., Siraj-Blatchford, I. and Taggart, B.
Final Report from the Key Stage 3 Phase: Influences on Students’ Development from Age 11-14 open_in_new
Effective Pre-School, Primary and Secondary Education 3-14 Project (EPPSE 3-14), DfE Research Report no. DFERR202, London: Institute of Education / Department for Education
Sylva, K., Melhuish, E., Sammons, P., Siraj-Blatchford, I. and Taggart, B.
Final Report from the Primary Phase: Pre-school, School and Family Influences on Children’s Development during Key Stage 2 (Age 7-11) open_in_new
Effective Pre-School and Primary Education 3-11 Project (EPPE 3-11), DCSF Research Report no. DCSF-RR061, Nottingham: Institute of Education / Department for Children, Schools and Families
Sylva, K., Melhuish, E., Sammons, P., Siraj-Blatchford, I. and Taggart, B.
The Final Report: Effective Pre-School Education, Technical Paper no. 12 open_in_new
Effective Provision of Pre-School Education (EPPE) Project, London: Institute of Education / Department for Education and Skills

Summary of effects

Meta-analyses Effect size FSM effect size
Camilli, G., Vargas, S., Ryan, S., & Barnett, W. S., (2010)
0.23 -
Gorey, K.M., (2001)
0.76 -
Nores, M., & Barnett, W. S., (2010)
0.31 -
Single Studies Effect size FSM effect size
Berlinski, S., Galiani, S., & Gertler, P. (2009)
0.23 -
Cattan, S., Crawford, C., & Dearden, L. (2014)
0.08 - GCSE performance
Claessens, A., Garrett, R. (2014)
0.71 - Reading (pre-school vs. childcare)
0.17 - Maths (pre-school vs. childcare)
0.44 - Writing (pre-school vs. childcare)
Gormley Jr, W. T., Gayer, T., Phillips, D., & Dawson, B. (2005)
0.79 - Letter-word recognition
0.64 - Spelling
Weiland, C., & Yoshikawa, H. (2013)
0.45 - Receptive vocabulary
0.62 - Early reading
0.58 - Numeracy
0.49 - Numeracy and geometry
Effect size (median) 0.47  

The right hand column provides detail on the specific outcome measures or, if in brackets, details of the intervention or control group.

Meta-analyses abstracts

Camilli, G., Vargas, S., Ryan, S., & Barnett, W. S. (2010)

Background/Context: There is much current interest in the impact of early childhood education programs on preschoolers and, in particular, on the magnitude of cognitive and affective gains.

Purpose/Objective/Research Question/Focus of Study: Because this new segment of public education may require substantial resources, accurate descriptions are required of the potential benefits and costs of implementing specific preschool programs. To address this issue comprehensively, a meta-analysis was conducted for the purpose of synthesizing the outcomes of comparative studies in this area.

Population/Participants/Subjects: A total of 123 comparative studies of early childhood interventions were analyzed. Each study provided a number of contrasts, where a contrast is defined as the comparison of an intervention group of children with an alternative intervention or no intervention group. Intervention/Program/Practice: A prevalent pedagogical approach in these studies was direct instruction, but inquiry-based pedagogical approaches also occurred in some interventions. No assumption was made that nominally similar interventions were equivalent.

Research Design: The meta-analytic database included both quasi-experimental and randomized studies. A coding strategy was developed to record information for computing study effects, study design, sample characteristics, and program characteristics.

Gorey, K.M. (2001)

Some scholars who emphasize the heritability of intelligence have suggested that compensatory preschool programs, designed to ameliorate the plight of socioeconomically or otherwise environmentally impoverished children, are wasteful. They have hypothesized that cognitive abilities result primarily from genetic causes and that such environmental manipulations are ineffective. Alternatively, based on the theory that intelligence and related complex human behaviors are probably always determined by myriad complex interactions of genes and environments, the present meta-analytic study is based on the assumption that such behaviors can be both highly heritable and highly malleable. Integrating results across 35 preschool experiments and quasi-experiments, the primary findings were: (a) preschool effects on standardized measures of intelligence and academic achievement were statistically significant, positive, and large; (b) cognitive effects of relatively intense educational interventions were significant and very large, even after 5 to 10 years, and 7 to 8 of every 10 preschool children did better than the average child in a control or comparison group; and (c) cumulative incidences of an array of personal and social problems were statistically significantly and substantially lower over a 10- to 25- year period for those who had attended preschool (e.g., school drop-out, welfare dependence, unemployment, poverty, criminal behavior). The need for a very large, well-controlled, national experiment to either confirm or refute these provocative, review-generated findings is discussed.

Nores, M., & Barnett, W. S. (2010)

This paper reviews the international (non-U.S.) evidence on the benefits of early childhood interventions. A total of 38 contrasts of 30 interventions in 23 countries were analyzed. It focuses on studies applying a quasi-experimental or random assignment. Studies were coded according to: the type of intervention (cash transfer, nutritional, educational or mixed); sample size; study design and duration; country; target group (infants, prekindergarten); subpopulations of interventions; and dosage of intervention. Cohen’s D effect sizes were calculated for four outcomes: cognitive gains; behavioral change; health gains; and amount of schooling. We find children from different context and countries receive substantial cognitive, behavioral, health and schooling benefits from early childhood interventions. The benefits are sustained over time. Interventions that have an educational or stimulation component evidenced the largest cognitive effects.