Gov. Jennifer Granholm’s fiscal year 2008 budget calls for a nearly $200 million increase in early childhood funding initiatives, bringing the early childhood budget to about $300 million, The money would go to school districts offering full-day preschool programs to children at risk, followed by mandatory full-day kindergarten the next year. Meanwhile, legislators are considering requiring all districts to offer full-day kindergarten.

Proposals for universal preschool and full-day kindergarten are an increasingly popular policy solution for everything from low academic achievement to reducing crime to lowering the dropout rate.

In short, research on preschool and full-day kindergarten shows that these programs have had meaningful short-term effects on disadvantaged students’ cognitive ability, grade-level retention and special-education placement. However, most research also indicates that the academic effects of early education programs disappear soon after children leave the programs.

The National Center for Education Statistics Early Childhood Longitudinal Study assessed 22,000 children at kindergarten entry and most recently reported on those students through the third grade. This research shows that by the end of third grade, the researchers no longer detect a difference between students who attended part-day or full-day kindergarten programs.

They write, "This report did not detect any substantive differences in children’s third-grade achievement relative to the type of kindergarten program (full-day vs. half-day) they attended." The finding holds across all subject matters tested. Third-grade reading, mathematics and science achievement did not differ substantively by children’s gender or kindergarten program type.

Similarly, the California-based RAND Corp.’s December 2006 report, "School Readiness, Full-Day Kindergarten, and Student Achievement," examined data from a nationally representative sample of almost 7,900 students and found "that full-day kindergarten programs may actually be detrimental to mathematics performance and nonacademic readiness skills."

The study established that "children who had attended a full-day program at kindergarten showed poorer mathematics performance in fifth grade than did children who had attended a part-day kindergarten program."

Evidence from other states that have made significant investments in universal preschool also cast doubt on the ability of universal preschool to fix long-standing problems with K-12 education. In New Jersey, for example, the 31 Abbott districts have been making a decade-long investment in public preschool. (The term "Abbott districts" originated with a New Jersey Supreme Court ruling that found the education provided to some urban school children was inadequate, and that mandated reform measures in certain districts. Those became known as Abbott districts.)

New Jersey’s Abbott districts spend the most money in the nation on prekindergarten education. Yet in 2005 more disadvantaged children in New Jersey scored below basic, which means they cannot read, on the fourth-grade reading assessment of the National Assessment of Educational Progress than in 1998. In 1998, 54 percent of students eligible for the free lunch program scored below basic on the NAEP reading exam. By 2005, 55 percent of students eligible for free lunch scored below basic. New Jersey’s significant investment in universal preschool in low-income Abbott districts has had zero effect to date on the bottom line of fourth-grade reading scores for disadvantaged children.

Similarly, in Oklahoma, which has also had a decade-long investment in universal public preschool, 47 percent of students eligible for the free lunch program scored below basic in 1998. By 2005, 50 percent of free-lunch students scored below basic.

Michigan reflects a similar pattern. Despite increased investments in preschool for disadvantaged children, more fourth-grade students in Michigan who qualify for free lunch scored below basic in reading on the NAEP in 2005 than in 1998. In 1998, 56 percent of free-lunch eligible students scored below basic on the NAEP; by 2005, 57 percent of free-lunch eligible children in Michigan scored below basic.

In Michigan, student performance is relatively high in the early grades. However, Michigan students have declining proficiency rates as they move toward high school. Test scores reflect a stair step pattern. Consider Detroit Public Schools, which has already made large investments in early education programs and full-day kindergarten. In 2007, 76 percent of third-graders were proficient in reading; in seventh grade only 57 percent of students were proficient in reading, and by high school only 48 percent passed the MEAP high school reading exam.

In addition, Education Week’s "Diplomas Count" reports that Detroit public schools have a graduation rate of 24 percent. The longer DPS children stay in school, the worse they do. These performance issues in the public school system are unlikely to be fixed with early education programs.

While preschool and full-day kindergarten may be politically popular, they are no silver bullet to fix the academic performance issues that plague this state. Michigan is considering investing hundreds of millions of taxpayer dollars each year in a program whose benefits disappear by third grade to solve education problems that come after the third grade. Shouldn’t policymakers be focusing scarce education resources on programs that can make a lasting difference?

Lisa Snell is director of education and child welfare at the Reason Foundation, Los Angeles, Calif.