Pre-K Helps Test Scores in Short Run But Hurts Them Later

By 07/19/2018

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The Arnold Foundation’s Straight Talk On Evidence web site provides a very useful summary of a recently published large RCT on a state-funded pre-K program in Tennessee. Consistent with a previous, nationally representative RCT of Head Start, this study found that students given access to government-funded pre-school by lottery initially score higher than those who lose the lottery on standardized test scores but then fare worse later.

In the TN study, treatment students score higher at the end of pre-K. But, as the Arnold summary puts it:

At the end of third grade, the study found statistically-significant adverse effects on student math and science achievement. In math, the VPK group scored 0.12 standard deviations lower than the control group, which equates to roughly 13 percent less growth in math achievement than would be expected in the third grade year. [ii] In science, the VPK group scored 0.09 standard deviations lower than the control group, which equates to roughly 23 percent less growth in science achievement than would be expected in the third grade year. [iii]

In an effort to explain the negative longer-term result, the authors suggest that special education may be to blame. Students admitted to the government-funded pre-K program were more likely to be labeled as needing special education services and that designation may have lowered academic expectations. But this explanation is inconsistent with Hanushek, Kain, and Rivkin’s finding that special education tends to improve test score results. Straight Talk at least considers the possibility that children being with family or in a non-government-funded pre-school may just be academically superior.

The hard reality is that the process of human development is complex and highly varied, so we just don’t know the optimal arrangements for all children. Andy Smarick has an excellent piece along these lines in the Weekly Standard, suggesting that education policy experts suffer from a Hayekian information problem. And this was also the subtext of my post last week on how parents are smarter than Technocrats. Even when Technocrats are armed with the best science, they generally do not have enough information to centrally plan the lives of others. This doesn’t mean that we never regulate anything. It just means that if we do regulate we should do so with great caution and large dollops of humility because the experts are typically missing a lot of important information that the individuals they are regulating are more likely to posses.

But caution and humility are no fun, so the Arnold Foundation’s Straight Talk chooses instead to double-down on Technocracy by suggesting that the disappointing results of pre-school as shown in RCTs of both Head Start and the TN program be remedied by identifying which subset of pre-schools seem to be more effective and regulating programs toward imitating those schools:

The above findings and observations, we believe, underscore the need to reform programs such as VPK and Head Start by incorporating (i) rigorous evaluations aimed at identifying the subset of local approaches that are effective, and (ii) once such approaches are identified, strong incentives or requirements for other local program sites to adopt and faithfully implement them on a larger scale.

Keep in mind that the TN program already has regulations in place meant to ensure quality, including requiring at least 5.5 hours of instructional time per day, a cap of 20 students per classroom, a licensed teacher in each classroom, and the requirement that schools choose among a state approved set of curricula. Also keep in mind that short-term test scores, which are the most common tool by which regulators monitor quality, showed positive results.

If these regulatory practices are insufficient to avoid harming students over the medium term, why would Straight Talk believe that doubling down on the Technocratic approach would make things better? It would be nice if they at least considered the possibility that we are suffering from a Hayekian information problem and may be unable to devise optimal arrangements for education.

— Jay Greene

Jay P. Greene is endowed chair and head of the Department of Education Reform at the University of Arkansas.

This post originally appeared on his blog.

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