There's a big downside to Gov. Nathan Deal's plan for cutting pre-K from six and a half to four hours a day as part of the effort to keep the HOPE scholarship program solvent.

This inconvenient truth jumps out from a new study by the Southern Education Foundation, a respected organization whose roots go back to Reconstruction. The study makes a very convincing case for not cutting Georgia's state-fund pre-K from a full day to a half day.

Since the program began under then-Gov. Zell Miller in 1997, "state funding has barely kept up with the steady, brisk growth of the number of four-year-olds in the state," the SEF study found. This year the program serves 84,000 children, about 57 percent of the four-year-olds in Georgia. But every year, limited funding by the state lottery has prevented the program from enrolling 7,000 to 10,000 children whose parents want them in pre-K.

There are some remarkable findings about this program: Georgia pre-K is not merely a babysitting service. Not at all. It produces results that might be astonishing to anyone unfamiliar with the program.

The study credits Georgia pre-K with having "a real impact on two important areas of public education in the state: reducing grade retention and dropouts." Without the pre-K program, "an average of more than 10,000 students each year would have repeated the same grade."

Aside from this huge educational benefit, pre-K more than pays its way: "The costs for K-12 education would have been an additional $35.6 million in 2010 without Georgia pre-K," SEF says. "During the next six calendar years - 2011 through 2016 - Georgia's public education budgets will realize savings of more than $212.9 million in tax revenues and expenditures because students who have been in Georgia pre-K have not repeated the same grade as often as other students."

The savings are unique because non-tax lottery money is used to fund the program. "Georgia pre-K is the one and only state government program which actually reduces tax expenditures without spending tax revenues today." The study cites economist Robert Lynch's cost-benefit study of a fully funded universal state pre-K program. Lynch estimated that "annual savings in state and local government expenditures would exceed the annual program costs of Georgia pre-K within two decades."

Yet, "for too long," SEF says, funding for Georgia pre-K "has failed to keep up with the inflation-driven cost of delivering a high-quality program to each student during the last 15 years." Per child expenditures have dropped from $4,895 in 1997 to $4,226 in 2011 - down $669 over the past 15 years!

While the HOPE scholarship program received a 35.7 percent increase in funding between 2008 and 2011, Georgia pre-K's funding inched up only 8.5 percent.

The SEF study concludes: "The Georgia General Assembly should maintain the existing Georgia pre-K program at current levels in the 2011-12 state budget with lottery funds." Then at the first sign of better economic times, pre-K should be expanded and strengthened.

There ought to be a better way.