It’s easy for educators following research on early-childhood education to get confused. District and school leaders that want to add or expand on-site preschool programs may especially be wondering how to best design a program when one study points to the lasting benefits of preschool and another seems to contradict it.

A new report from the Learning Policy Institute (LPI) seeks to clarify what sometimes feels like conflicting research on early learning programs, especially those that are publicly funded.

“Untangling the Evidence on Preschool Effectiveness: Insights for Policymakers” includes a comprehensive review of existing studies and highlights what specific benefits — such as literacy and math skills, placement in special education and grade retention — they were able to measure.

“Sorting out these findings requires an examination of the way that different studies construct comparison groups — whether children in those groups are truly comparable to the children who attended the preschool program under study and whether they themselves attended a different preschool,” the authors write.

The report, however, also focuses more specifically on two studies that found disappointing results for children who participated in a particular model. The first is Head Start — a 2012 impact study showed that by the time former Head Start students reached 1st grade, most were not performing noticeably better in school than a sample of similar children from low-income families that did not attend the program, which provides early-childhood education and other resources to this student population and their families.

While critics have sometimes used these findings as a reason to cut the program, one explanation for the results is many children in the comparison group still went to some type of early learning program, whether it was Head Start or something else. Another look at the data showed that when Head Start students were compared to 3- and 4-year-olds that didn’t enroll in any program, there were much larger gains for former Head Start participants by 1st grade, specifically in vocabulary. Another study found that the benefits of spending increases on Head Start can persist through adulthood, especially when the children went on to attend better-funded elementary schools.

Tennessee’s Voluntary Pre-K (VPK) also received negative attention recently when researchers at Vanderbilt University found that children who didn’t attend the program were actually performing better on state assessments in 3rd grade than those who did. VPK students were also more likely to be referred to special education in elementary school than those who didn’t attend.

These results continued the pattern seen in earlier studies of the program. LPI’s report provides several explanations for the disappointing findings, suggesting, for example, that when children are involved with the public school system at earlier ages, it’s more likely that educators will identify developmental delays. The Vanderbilt researchers also concluded that once a child receives a special education label, it’s difficult to lose it.

Secondly, the comparison sample of children tended to differ in a variety of ways from the VPK study sample — they were more likely to be white and less likely to be English language learners. Researchers following the VPK program have also found wide variation in the quality of VPK classrooms, which could also lead to negative effects.

Acting on the results

A Tennessee lawmaker is, in fact, using those results as the basis for a bill that would allow districts to spend money meant for pre-K on other areas in the early grades, such as reading specialists or smaller kindergarten classes.

The state, however, is working to implement a 2016 state law that prioritizes VPK, which serves more than 18,000 children, and improving some of its areas of weakness. It requires districts to compete for pre-K grants and create stronger connections between pre-K and the early grades. The legislation also added more emphasis on professional development for teachers.

Since the law's passage, the state education agency has taken multiple steps to increase the quality of the VPK program, Chandler Hopper, a spokesman for the Tennessee Department of Education, wrote in an email. These include offering three webinars for districts on how to complete new VPK applications, revising early learning standards to connect with the K-12 system and narrowing the choices of approved curricula from 37 to three. The state has also published a document on quality early-childhood programs to serve as a guide. 

'Development is complicated'

W. Steven Barnett, the senior co-director of the National Institute for Early Education Research (NIEER), offers additional reasons why studies of preschool programs sometimes show few benefits.

“Researchers often have done a very poor job of measuring what children receive in those programs, so we don't know what content they were taught or activities they experienced,” he wrote in an email. “We almost never have decent measures of intensity.”

He added that family characteristics and other experiences children have while enrolled in a pre-K program varies considerably, but “rarely are measured.”

Linda Smith, the director of the Early Childhood Initiative at the Bipartisan Policy Center in Washington, added in an interview that measuring outcomes among young children is inherently tricky.

“Development during early childhood is complicated and it doesn’t happen in a linear fashion,” she said, adding that researchers “try to isolate certain aspects of development and that makes it even worse.”

Because young children change and develop so quickly, a toddler or preschooler who doesn’t demonstrate a certain skill or behavior one day can make large strides in that area within a few weeks or months, Smith said. She also noted that more training for K-3 teachers on child development could help educators become more skilled at building on what students gain by attending pre-K.

A recent report from New America, for example, described how the Boston Public Schools is doing this by connecting concepts from the end of one grade to the beginning of the next, bringing together teachers from across the primary grades to learn over the summer and providing teachers new to the district or in the early grades with coaching throughout the year.

‘Moving beyond the question’

An important takeaway from the VPK research — and studies on early-childhood in general — is how programs are designed matters, the LPI authors write.

“The evidence supports moving beyond the question of whether preschool ‘works’ and focusing instead on the more pressing question of how to design and implement programs that ensure public preschool investments consistently deliver on their promise,” they write.

These questions are especially relevant for the growing number of cities opening and expanding pre-K programs. A report released last week by NIEER and CityHealth, an initiative of the de Beaumont Foundation and Kaiser Permanente, showed that of the 40 major city pre-K programs examined, five — Boston, Charlotte, Nashville, New York and San Antonio — meet many recommended indicators of quality and enroll a significant proportion of eligible children.

Programs in another eight cities were recognized for requiring elements of quality — in areas such as teacher preparation and salary, class sizes and ratios, and health and developmental screenings. However, they were not widely accessible to children.

“Cities that have not yet developed a Pre-K program should design their programs with an eye toward these proven quality benchmarks,” the authors write. “Doing so will ensure that local Pre-K programs are as effective as possible in achieving long-term benefits.”