Photo credit: Dan Harr / Splash News/Newscom

President Obama announced a major effort to expand government preschool early this afternoon. The plan would create a “continuum of child care for children from birth to age 5.”

Expanding government preschool, particularly federal preschool, is wrought with problems. Any expansion of government preschool, whether state or federal, comes at the expense of private providers, who must compete with “free” government programs. When the private provision of care is pushed out of the market, that ultimately means fewer choices for families.

Moreover, taxpayers and parents already know what big government preschool looks like: the federal Head Start program. Head Start has had no long-term impact on the cognitive abilities of participating children, has failed to improve their access to health care, has failed to improve their behavior and emotional well-being, and has failed to improve the parenting practices of parents. And this is according to scientifically rigorous evaluations by the program’s own administering agency, the Department of Health and Human Services.

Sadly, the limitations of preschool aren’t unique to Head Start. Georgia and Oklahoma—the two states in the nation that currently have the type of expansive preschool President Obama is proposing—have failed to see benefits accrue from the hundreds of millions of dollars their taxpayers spend annually. In Oklahoma, families have actually seen reading scores decline among children after implementing universal preschool.

The Obama Administration and proponents of expanded preschool turn to the Perry Preschool Project and the Abecedarian Project (conducted 40 and 30 years ago, respectively) as evidence of the merits of government preschool.

Perry and Abecedarian were high-intervention preschool programs attended by a handful of children who were then tracked through adulthood. As Russ Whitehurst at the Brookings Institution writes, “Perry and Abecedarian were multi-year intensive interventions whereas state pre-K programs are overwhelmingly one year programs for four-year-olds. Costs per participant for Perry and Abecedarian were multiples of the levels of investment in present-day state programs, e.g., $90,000 per child for Abecedarian.”

While these two programs did have positive results, these results have not been replicated in state preschool programs. In fact, no randomized experiments of state preschool programs exist.

Generalizations from interventions such as Perry and Abecedarian are what Whitehurst refers to as “prodigious leaps of faith.”

So if there is thin evidence of a positive impact of preschool, and, if Head Start is our guide, no evidence of a positive impact of big government preschool, who are the beneficiaries?

Expanding the underperforming K–12 system “down” a year earlier to include publicly funded preschool naturally benefits the education unions. An extra year of public education means an untold number of additional public education employees.

The majority of America’s young children already attend preschool, and new federal spending to expand day care and preschool would be an expensive and unnecessary middle-class subsidy. Demand for new, large-scale government spending on early childhood education and care is not evident. Families seem to prefer caring for their children at home in their early years—80 percent of mothers who work part-time indicate that they prefer to stay home when their children are young.

Expanding government preschool would be unlikely to improve academic outcomes for children, would put taxpayers on the hook for untold billions in new spending, and would crowd-out the private provision of preschool, ultimately limiting choices for families. It’s something many scholars agree is bad policy. As The Wall Street Journal reported yesterday:

Most other academic studies have also found early educational interventions “fade out” and that those programs rarely achieve what they promise. Russ Whitehurst of the Brookings Institution wrote Wednesday that the available studies supporting universal pre-K were “thin empirical gruel.” Researchers at the Heritage Foundation and the conservative sociologist Charles Murray have come to similar conclusions. This is about as close to an intellectual policy consensus as Washington gets.

Let’s hope President Obama agrees.