Michigan will save $39,000 in public costs for every high-risk child in pre-kindergarten — $100,000 in Detroit — according to a Fisher Foundation report. These “investment” claims should  be taken with a grain of salt, writes Sara Mead, who links to Lisa Guernsey’s analysis of the claim that preschool saves $10 for every $1 spent.

Very high-quality programs — which are not the norm — can improve outcomes for high-risk kids, Mead writes. But only 3 percent of savings from improved school readiness flow to K-12 schools, the report estimates.

. . . the really flashy high-value savings come from benefits far down the road, such as reduced crime and prison costs, (that) are hard to capture to pay for pre-k. And when early childhood advocates cite such diffuse and distant benefits to claim that the “value of investing in school readiness for just one child at risk of academic failure in Detroit, Michigan, is…about $100,000,” I worry that the perception such claims are oversold may actually increase skepticism about the value of pre-k investments, rather than building support.

It’s more persuasive to cite immediate savings to the school system, Mead argues. The Fisher researchers estimate pre-k saves $2,374 per child in reduced special education and grade retention costs, $3,376 in Detroit.  Michigan spends about $4,453 per child in pre-k. If that’s true, pre-k isn’t free but it’s awfully cheap.