In educational research the use of comparative and meta-analysis methods allows researchers to draw conclusions about educational practices using a quantitative synthesis across studies. Such methods "… help draw conclusions about whether an intervention or approach, on balance, is effective or not … [and] explain variation in research findings by identifying any patterns or significant associations with features of interventions associated with greater or smaller effects" (Higgins, 2016, p. 32)

While there has been significant growth in early education research in Ireland, it is still at the nascent stage when compared to other fields of education research and there are few research evaluations with the design potential to be studied comparatively.

This research summary reports a study that was devised to carry out a comparative analysis using a section of quantitative findings from the evaluation of the Tallaght West Child Development Initiative (CDI) Early Years programme (Tallaght West Childhood Development Initiative, 2017), along with datasets from the UK Effective Provision of Preschool Education (EPPE; Melhuish, Sammons, Siraj, Sylva, and Taggart, 2014) and Effective Pre-school Education Northern Ireland (EPPNI) studies. This internationally comparative study was funded by the Children’s Research Network Prevention and Early Intervention Research Initiative Senior Scholars Grant Scheme 2018. The CDI Early Years project was one element of a wider area-based initiative developed to meet the needs of young children and their families growing up in a designated disadvantaged area of Dublin. The CDI Early Years project provided a two-year programme for two-and-a-half to three-year-old children. It offered, among other features, a manualised programme that followed the High/Scope Curriculum and a dedicated Speech and Language Therapist.

The CDI evaluation (Hayes, Siraj-Blatchford, Keegan and Goulding, 2013) was designed to allow for comparison with elements of the EPPE and EPPNI datasets (see footnote). This approach aimed to mitigate any shortcomings associated with a medium sample size and the short duration of the study. The evaluations of all three initiatives share common dimensions across a series of evaluation instruments. At the child level shared measures include dimensions of the British Abilities Scale (BAS II; Elliot, Smith and McCullough, 1996) and the Adaptive Social Behavior Inventory (ASBI; Hogan, Scott and Bauer, 1992); at the parent level they include the Strengths and Difficulties Questionnaire (SDQ; Goodman, 1997) and the Home Learning Environment Inventory (HLE - Adapted; Melhuish, Sylva, Sammons, Siraj-Blatchford and Taggart, 2001); and at setting level they include the Early Childhood Environment Rating Scales (ECERS – Revised; Harms, Clifford and Cryer, 1998). By quantifying the degree to which the outcomes at comparable points are similar (or different), the study intends to statistically extrapolate what the results might have been, had the CDI evaluation study extended for a longer period allowing data collection as the sample children progressed through into primary school.

While there are points of commonality across the evaluations, there are also differences. In the first instance, the CDI evaluation explored the impact of an early intervention programme, whilst the EPPE evaluation studied the impact of preschool provision in general. However, there are subsample data from the UK studies which relate specifically to Local Authority preschools, often in receipt of additional supports when compared to mainstream UK preschools. Secondly there is a ten-year difference in the data collection points; the preschool data for the EPPE study were collected in the early 1990s; in comparison, the CDI data were collected from 2008-2011. Finally, there is a substantial difference in the sample sizes across the studies. We are currently comparing the datasets across the comparable dimensions and developing the analytical framework to test the extent to which the ambitions of the CDI design can be realised. If successful, locating the findings of the CDI evaluation within an international context will provide an expanded and enhanced context for interpreting and disseminating the CDI data nationally and internationally. Furthermore, the results will further to our understanding of what aspects of preschool experience contribute to positive outcomes for children and inform policy initiatives to enhance the impact of early childhood education and care. The findings will be disseminated through publication and relevant conferences.