Despite a far stronger research record and far lower costs to taxpayers, other activities are not encouraged at anywhere near the level of government preschool programs.

Latest results from the first randomized control trial of a state pre-kindergarten program found participants’ early gains quickly transformed into worse academic performance, more discipline problems, and higher special education placements than children who hadn’t participated. By second or third grade, the nearly 3,000 children studied who participated in Tennessee’s Voluntary Pre-K Program (TNVPK, or VPK) had statistically significant negative results compared to peers who mostly stayed home with their families.

“One possibility is that, contrary to conventional wisdom, some children may be better off academically if—instead of attending public pre-k—they stay at home at age four,” says a study summary from the Arnold Foundation’s Straight Talk on Evidence research clearinghouse (h/t Jay Greene).

Tennessee’s pre-k program was touted as a national model long before high-quality studies could be completed to test that assertion. That is typical of preschool advocacy, which is lush with foundation and government funds but low on reliable, replicable benefits to children and taxpayers. Partly because of this persistent PR push, two-thirds of four-year-olds and two-fifths of three-year-olds currently attend pre-primary programs. Half of that number are enrolled in government programs, a proportion that has grown rapidly in the past few decades despite parallel growth in government debt and deficits.

Benefit Promises Based On Hope, Not Experience

Tennessee’s pre-k program began in 2005. The state legislature immediately expanded it the next year, then funded a doubling of enrollment just two years later, before any reliable research could possibly be conducted. Today, 18,000 “at-risk” four-year-olds are enrolled.

Politicians like Obama Education Secretary Arne Duncan and other people paid to advocate government taking over child raising have praised Tennessee pre-K and said it should be a model for expanding such programs everywhere. The state’s pre-K information page says the program is “recognized as a national leader in pre-K quality.” The Straight Talk study summary notes “the program’s quality appears to be fairly typical of state pre-k programs around the country.”

“Critics of our study have argued that the effects reflect the unusually poor quality of the TNVPK program. We demonstrate that measured classroom quality in the TNVPK classrooms was virtually identical to that in programs that have been lauded by pre-K advocates,” the Vanderbilt University authors noted in discussing earlier negative results they found during this nine-year study.

In 2014, The New York Times said it’s become standard for both Republican and Democrat politicians to support pre-K spending as an essentially vote-buying tactic. The article also noted advocacy groups have snookered business leaders into believing that preschool can help address the social fallout from America’s increasingly degraded family relationships, particularly the spike in children born to unmarried mothers and harm to children of normalizing divorce. Business leaders also have incentives for taxpayers to subsidize working mothers: doing so takes pressure off them to negotiate employment conditions more favorable to mothers and increasing the labor pool depresses wages.

More Details About the Study Findings

At the end of one year in Tennesee’s pre-k, participating children scored better on academic measures than non-participants did, such as letter recognition and sounds. But during just one year of kindergarten, non-participating children not only caught up to the preschooled children but surpassed them. This effect persisted through third grade, where “VPK participants scored lower on the reading, math, and science tests than the control children with differences that were statistically significant for math and science.”

“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,” the Straight Talk summary explains. “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.”

The study also found that preschooled children had more negative feelings about school in first grade, broke school rules more often, had more language problems especially in kindergarten, than peers who didn’t attend the state program. Of the children studied who did not attend the Tennessee program, “63% received home-based care by a parent, relative, or other person; 13% attended Head Start or what parents described as a public pre-k program; 16% were in private center-based childcare; 5% had some combination of Head Start and private childcare; and childcare for 3% was not reported.”

As for special education placements, it was unclear from the study whether slightly higher special-ed labeling for preschool attenders was because attending preschool caught existing problems earlier or children were overlabeled as special needs simply for being younger and less mature. The authors note: “the overwhelming majority of special education designations in VPK were for speech and language issues, a domain in which development is especially varied for 4-year olds. Once a child has received a special education designation, it is difficult to lose it.”

Why This Study Deserves More Weight than Others

While preschool-pushers insist that results like this don’t match the “consensus” of people whose job security and prestige are contingent upon government funding advocacy research and consuming more of family life, the two only large-scale, gold-standard studies of government preschool unanimously find long-term disadvantages to children.

The authors of the Tennessee study explain the disconnect by noting that most studies on preschool programs either focus on immediate rather than long-term effects or extrapolate from two boutique, decades-old, and very expensive experiments that produced small, unreplicated benefits to their approximately 100 total participants. The authors’ discussion of the significant weaknesses of studies that supposedly substantiate the current “consensus” is worth reading.

“When dealing with a voluntary program with children’s participation always a matter of self-selection by parents, it is difficult for researchers to ensure that they are comparing outcomes for pre-k participants and nonparticipants who are similar in all ways that matter prior to their differential pre-k experience. The result is an uneven and inconclusive research literature,” they note.

By contrast, the Tennessee study was able to randomize its sample and provide a control group because more people applied than the program could accept. So slots were randomly offered and both participants and applicant nonparticipants were studied, providing a rare opportunity for the most rigorous study possible because the only noticeable difference between the two groups was joining or not joining the program.

Attempts to Suppress Study Findings Almost Work

Bias in the early childhood field almost suppressed this study’s findings. In a study note, the authors explain that when their early findings were positive, they received loads of excited attention from media and academia. But when their longer-term findings, out in 2015 and this spring, showed a reversal of the initial benefits the Vanderbilt researchers received massive pushback.

[Later negative] findings were not welcome. So much so that it has been difficult to get the results published. Our first attempt was reviewed by pre-k advocates who had disparaged our findings when they first came out in a working paper – we know that because their reviews repeated word-for-word criticisms made in their prior blogs and commentary. We are grateful for an open-minded editor who allowed our recent paper summarizing the results of this study to be published (after, we should note, a very thorough peer review and 17 single-spaced pages of responses to questions raised by reviewers).

Randomized control trials are considered “the gold standard” of medical and social science research because they offer the highest reliability of results. The only other such high-quality study to be conducted on government preschool programs, the federal evaluation of Head Start, found similar results. What a surprise: that federal evaluation’s results were also delayed and suppressed.

The Tennessee and federal studies provide “uniquely credible evidence on the topic,” says the Straight Talk summary. “Other studies of public or private preschool programs have had weaknesses that limit the reliability of their findings, such as lack of random assignment (e.g., Oklahoma universal pre-k, Chicago Child-Parent Centers) or small samples and imperfect randomization (e.g., Perry Preschool Project, Abecedarian Project).”

The Best Research Supports Parenting, Not Childcare

While people paid to advocate government preschool responded with one of their standard lines, that the results merely indicate the need to spend more and try harder, the study authors note “we do not yet have a basis for improving state-funded pre-k programs that is grounded in empirical evidence relating program characteristics to child outcomes.” In other words, we have no reliable research that tells us how to improve preschool programs, so any efforts in that direction are essentially stabs in the dark.

Indeed, the evidence we do have suggests that kids would be better off at home, even if their families have less money than others do. In its research review, the study cites research that shows parents of all income levels have stepped up their parenting game in recent decades, possibly making older study findings, the source of most positive results, obsolete.

Comparing 1998–2010, [other researchers] found that parents increasingly structured their children’s experiences to focus on learning opportunities such as those that involve computer access, more books in the home, and enrichment activities organized specifically for children. It is especially notable that the socioeconomic gap in these practices narrowed over this period with low-income parents showing stronger increases in their investments in their children than more affluent parents.

This conclusion is also bolstered by the academic literature finding that adoption is the number one most effective way to improve a deprived child’s life outcomes. Since, of course, adopted children don’t share their adoptive parents’ genetics, the major boosts they get from being adopted have to come exclusively from a combination of environment and parenting. So if parenting is likely what’s going on here, perhaps efforts would be better directed that way instead of towards removing children from homes, especially since parents are already getting aboard that train.

Another reality, one of the best-documented in social science, is that children who live with their married, biological parents are the best protected against virtually all negative life outcomes. Reading to small children and turning off screens also have well-documented positive effects. These are things that almost all parents can do for their children, yet despite their far stronger record and far lower costs to taxpayers they are not encouraged at anywhere near the level of government preschool programs. For the best interests of children and society, that ratio needs to flip, stat.

The study authors also pointed out, as preschool skeptics have for decades, that the persistent fade-out of any positive effects indicates it’s pointless to add preschool to government education until the upper grades are more effective: “It is doubtful that anything done in pre-k can have sustained effects if the gains made there are not supported and extended in the schooling that follows.”

Pew Research Center polling finds 59 percent of American adults think the kids are better off when one parent stays home to raise them. It looks like the research supports their common sense.