The evidence continues to mount: Investing in the youngest learners is one of the best, most cost-effective ways to improve education.

This week, a Wilder Foundation research study added fuel to that fire with more reasons to support quality preschool. Commissioned by the Bush Foundation, the report focused on quantifiable costs within Minnesota’s K-12 system. It found that annually schools lose: $42 million of per-pupil state aid when students drop out; nearly $30 million in teacher-related costs because of high rates of absenteeism and turnover and higher pay for teachers working with more challenging students; $24 million for special education and grade repetition; $11 million to serve English language learners with no preschool education, and $6 million on problems associated with delinquency.

That adds up to $113 million that could be saved or put to better use educating preschoolers. For example, as the report points out, that amount could finance a one-year-program for all the state’s low-income children.

Wilder researchers say their cost estimate is conservative because many expenses cannot be quantified. How much more in time and resources do schools use to try to bring children up to speed? What about the costs when parents take their kids out of public school because of behavior or safety problems?

This recent data is consistent with earlier local and national studies. Research by local economists has shown that for every $1 spent on good preschool for at-risk kids, $7 to $16 are channeled back into the economy. A state-by-state study of 2007 dropouts found that students who leave school in Minnesota will cost the state nearly $4 billion in lost wages and taxes over their lifetimes. If students of color here graduated at higher rates, more than $1.3 billion could be added to the state’s economy.

And the national group, Pre-K Now, has documented how low educational attainment threatens American workplace competitiveness. According to its research, good universal programs for 3- and 4-year-olds would, over the next several generations, create 3 million jobs, increase annual U.S. earnings by $300 billion and raise America’s GDP by about $1 trillion.

Minnesota lawmakers and others have raised awareness and support for early education in recent years. In 2007, the Legislature restored about $8 million of previous cuts to Early Childhood and Family Education programs and increased aid to Head Start. And lawmakers provided about $32 million to get a start on all-day kindergarten, though nearly 10 times that much is needed to offer it statewide.

The state should step up its pre-school support, but cannot do it alone. Lawmakers must work with school districts, private entities and nonprofits to coordinate the expansion of quality preschool.

Investing in good early education is cost-effective, and it brings high returns for the students, society and the economy. That is why, even in challenging economic times, government and others must find ways to provide more top-notch pre-school options for Minnesota kids.