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Some days ago, the National Bureau of Economic Research published an article on the long term impacts of public and universal pre-school education programs on the lives of children. The study took place in Boston, in the United States of America, but holds particular relevance to the Portuguese context as it analyses a model that is very similar to the situation in Portugal. Nevertheless, just what types of impact are we referring to?


Attending pre-school compensates. In the short term, the advantages for the cognitive and socio-emotional development have been systematically corroborated by various different studies. However, what about the long term? What effects and impacts might pre-school education have on the life of a person?

A very recent study, published in the National Bureau of Economic Research, approaches precisely this question through analysis of a program to roll-out pre-school teaching in Boston, in the United States of America.

The study by Gray-Lobe and co-authors demonstrates that general access to public pre-school may have important impacts on the lives of children over the long term. Despite this study being among the first to apply a random sampling method to study the long term impacts of pre-school education, the results closely resemble those of other recent studies based on different methodologies. The earlier randomised studies focused on high intensity programs operating on a small scale, such as Perry Preschool or Carolina Abecedarian, launched in the 1960s and with samples of around 150 children coming from very poor families or with only limited scopes of analysis and short term results. Other studies examining large scale programs focus on pre-school programs targeting poor sections of the population – for example, the American program “Head Start” – and deploy comparisons among siblings, covering restricted geographic dimensions or discontinuous regression designs.

The study by Gray-Lobe and co-authors compared children who entered pre-school at four years of age between 1997 and 2003 through a lottery providing access to pre-schools with the number of applicants exceeding the number of places available – thus, with waiting lists. As regards the other children left on waiting lists, those who were (randomly) selected for pre-school registered a greater likelihood of enrolling in university, in preparatory programs for university access, better results in university access tests and a higher probability of completing secondary school at the right age. Attending pre-school also cuts the incidence of various coercive measures, such as serving youth custodial sentences. However, there were no detectable impacts on the scores recorded in performance tests taken between the third and eighth years of schooling.

Analysis of the subgroups also conveys how these effects, such as university enrolment, doing university access preparatory tests and in preventing legal offences were greater for males than for females and did not register any differences by socioeconomic level.

The program studied by these authors is particularly interesting due to its similarities with the public pre-school model provided in Portugal and in many other European countries. Pre-school in Boston is universal, open to all the children residing in the region irrespective of their household income and for a period of six hours per day. In practice, the program attracts a relatively disadvantaged student population with a large proportion of non-white students and from low income households.

There is still only scant evidence for grasping how universal programs affect participants over the long term. The evidence available from contemporary programs in Europe suggests that the expansion of access to pre-school education and formal creches may also benefit the cognitive and socio-emotional development of children. However, this evidence only covers high income countries, for example such as the expansions undertaken in Norway in the 1970s and 1990s and in Germany.

While documenting positive impacts measured in terms of both behaviour and educational performance, Gray-Lobe and co-authors leave open the mechanisms through which the program produced these positive impacts as do many of the aforementioned studies. Various hypotheses have been put forward to illustrate the potential mechanisms even while this requires more detailed studies that include information on the family and household environment and the quality of the pre-school teaching.

This leaves open various possibilities. Firstly, attending public pre-school may have provided the children with access to a better educational environment than the alternative without the public system; nevertheless, we are unable to ascertain whether this alternative would be a worse quality pre-school or simply being cared for by their mother or grandparents. Secondly, the mothers may have (re)entered the labour market in keeping with the opportunity to put their children into pre-school and this may have driven an increase in the household income and, consequently, reducing stress levels in the family. Finally, it is also possible that the parents learned new and better forms of interacting with their children in the house through contact with pre-school and that this fostered a better domestic environment.


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