Interventions that only provide material resources to preschools may fail to achieve any benefits, and have unintended negative consequences, if teachers have insufficient training

Well-designed early child education programmes can have substantial and long-lasting positive effects on children (Elango et al. 2015). However, low-quality early child education programmes may deliver few benefits for child development and can even be inferior to homecare (Araujo & Schady 2015). As governments around the world, especially in low- and middle-income countries, expand coverage of early child education programmes, quality should be a first-order concern. However, most of the existing research focuses on the impact of early child education programmes relative to homecare; few studies are concerned with understanding which aspects of early child education programmes are most important for child development or on the effectiveness of specific improvements to existing programmes.

In our recent work with the government of Colombia (Andrew et al. 2022), we use a randomized field experiment to compare two approaches to improving the quality of public preschools attended by relatively disadvantaged children. The first, designed by the Colombian government and rolled out nationwide, provided targeted preschools with significant additional funds, earmarked primarily for hiring teaching assistants (TAs). The second, designed and funded by a nongovernmental foundation, complements the first by additionally providing professional development (PD) training for the existing preschool teachers. We find that provision of funds alone had no positive impacts on child development, despite high compliance with the hiring directive. However, we show that the addition of the PD training, at moderate extra cost, did have significant positive impacts on child development.

The setting

Our focus is on partially-subsidised government preschools – Hogares Infantiles - for children between the ages of 18 months and 5 years, from middle-to-low socioeconomic-status families. Although these preschools deliver higher quality services than some of the other childcare providers in Colombia, they are still characterised by relatively large class sizes; low levels of teacher training, supervision and monitoring; a lack of a structured curriculum; and insufficient emphasis on pedagogical activities in the classroom. While teachers in these preschools have a significant amount of autonomy over how they organise their day in the classroom and how they utilise available resources, they have a high workload, with many reporting that they frequently work overtime.

The interventions

In 2010, the government of Colombia started a comprehensive strategy to improve early childhood policies. In 2011, as part of this strategy, Hogares Infantiles were given a substantial amount of additional financial resources (equivalent to a 30% increase in per child expenditure). Of this, the largest pot of money was earmarked for hiring teaching assistants (TAs), rarely used in Hogares Infantiles prior to this programme. Additionally, a well-established Colombian NGO, Fundación Éxito  and the Colombian National University, developed a PD training programme for existing Hogares Infantiles teachers to complement the new resources for TAs. In response to a concern that teachers allocated too much class time to basic caregiving activities, the programme placed strong emphasis on the importance of focusing on quality interactions and activities that promote child development and learning during class time. The cost of the PD programme is much lower than the cost of the TAs.

We worked with the government and Fundación Éxito to embed a randomized controlled trial (RCT) into the initial rollout of these programmes. A random subset of Hogares Infantiles were wait-listed to receive the government programme 18 months later and a random sub-set of Hogares Infantiles  receiving the TA programme first were selected to also receive the PD programme through Fundación Éxito.

Main findings

We found that, after 18 months, the additional resources provided by the government for hiring had no significant impacts on any of our 7 measures of cognitive and socio-emotional development of children aged 18-36 months at baseline. There is no evidence of any heterogeneity in this finding by child baseline socio-economic status or level of development. We do, however, see significant improvements in child development when the government TA programme was complemented with a teacher PD programme.  After 18 months of exposure to this package, we find an improvement in children’s cognitive development equivalent to 0.17 of the control group standard deviation (Figure 1). In line with several other studies (e.g. Havnes and Mogstad 2015, Cornelissen et al. 2018, Felfe and Lalive 2018), children from poorer families benefited the most: these children’s cognitive development improved by, on average, nearly a third of a standard deviation.

Figure 1: Programme impacts on children’s cognitive development (standard deviation).

Notes: Ranges show 95% confidence intervals.

These are non-negligible impacts. To the extent that credible comparisons can be made between studies, 0.17 standard deviations corresponds to 23% of the achievement gap between children in the top and bottom wealth quintiles in Colombia at age 6 (Rubio-Codina and Grantham-McGregor 2019) and is in the ballpark of studies that evaluate effects of centre-based relative to homebased care in Colombia (Nores et al. 2019) and other Latin American countries (e.g. Noboa-Hidalgo and Urzúa 2012, Behrman et al. 2014). There is little to guide extrapolation of how these short-run impacts might map onto long-run outcomes of children in Colombia. However, evidence from further afield, such as evaluations of Head Start or of the Perry Preschool Programme in the USA, suggests that programmes that achieved short-run effects of similar magnitude can have wide-ranging and persistent positive long-run effects (Garcia et al. 2021, Deming 2009).

To understand more about these impacts, we investigate how the programmes affected teacher behaviour. We find that in the TA only arm, there was a reduction in the amount of time that teachers spend in the classroom with the kids, including on learning activities that are strongly positively associated with child development. The impacts are significant and sizeable: a 0.35 standard deviation reduction in frequency of doing learning activities with the children; 0.85 standard deviation reduction in the frequency of personal care activities and a 42% reduction in teacher-reported overtime (relative to the control group mean). The addition of the PD programme offsets the negative impacts on activities that are conducive to child development (learning and overtime) so that in this arm we only see a reduction in the amount of time that teacher spend on caregiving routines relative to the control group. There is also a significant improvement in the quality of activities teachers do with the children (Figure 2).

Figure 2: Impacts of the two programmes on teacher activities and quality of teaching

Notes: Ranges show 95% confidence intervals.

Taken together, these results suggest that teachers’ behavioural reactions are key for understanding both the null effects of the TA only programme and the positive effects of the TA + PD package. They are consistent with the idea that, in the TA only arm, teachers used TAs to substitute their time in all activities, irrespective of the importance of these activities for child development or the training and experience needed to execute them well. The training delivered through Fundación Éxito , however, may have provided teachers with a better understanding of the process of child development as well as making their engagement with children more effective. Ultimately, this enabled them to integrate the TAs into the classroom and adapt their own activities in a way that was conducive to improvements in children’s development.

Our work complements a recent set of studies showing that programmes which provide teachers with TAs can be effective at improving learning outcomes (e.g. Banerjee et al. 2017, Duflo et al. 2020). However, our analysis suggests that in contexts where teachers are poorly trained, additional school resources like TAs need to be accompanied by guidance on how to utilise them.  Without it, they might generate unintended and undesirable consequences, such as the reduction in effort that we see among teachers in the TA only programme.

Policy implications

This study adds to a small evidence-base on the effectiveness of different approaches to improving preschool quality in low- and middle-income countries and an even smaller evidence-base on ones that can be implemented at scale within existing service delivery infrastructures. In the context of ongoing roll-out of pre-school access across low- and middle-income countries, the need for such evidence is increasingly pressing.

Furthermore, given the relatively low additional cost of the PD programme, our evidence provides a concrete, scalable way in which the government of Colombia could improve a national programme to deliver much better outcomes for children.

Finally, our results highlight two key broader points. First, they provide a stark reminder that it is not enough to invest significant resources in preschool improvement – details of the specific programme design really matter. Our results suggest that investment in quality of teacher-child interactions is particularly important. Second, careful consideration of features of the context and how these may influence behavioural responses of those targeted by the interventions is critical for achieving the intended impacts.  


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Education Training Colombia Child Development Pre-schools Teachers