A prominent conservative state senator wants to end the expansion of 4-year-old kindergarten in Wisconsin, citing multiple studies critics say are inaccurate and have a conservative bias.

Sen. Glenn Grothman, R-West Bend, asked Gov. Scott Walker to stop state policy encouraging 4K late last month after reports surfaced showing a new Madison 4K program would cost $10 million a year for state and local taxpayers.

“As other districts around the state make the same decision, the bill will still go higher,” Grothman said in a statement.

Beth Graue, professor of curriculum and instruction at the University Wisconsin School of Education, said investment in 4K has researched and proven benefits.

“Most scholars would say the investment in 4K is one that will provide positive outcomes in the long term,” Graue said. “I recognize the state is in a huge economic crisis, but the evidence [Grothman] brings forward does not match scholarly evidence.”

Studies from The Pacific Research Institute and the Reason Foundation, both free market think tanks, show the benefit of 4K does not survive past the child’s eighth or ninth birthday, Grothman said.

A report on Oklahoma’s 4K program, one of the best in the country according to Grothman, showed 4th grade students’ reading comprehension levels dropped, proving 4K is not the end-all, be-all.

Those who say otherwise are predisposed by their own interests, Grothman said.

“They’ll find studies that say 4K will be better, but you have to be skeptical,” Grothman said. “People with the school of education want it so they always have new teachers to instruct.”

Graue said she is not interested in bringing more clients to the school of education and the amount of scholarly research siding in favor of 4K education is vast.

“I have vested interest in the welfare of kids in the state of Wisconsin.” Graue said. “There is enough research proving the benefits of 4K to bury you with.”

Investing in 4K has money-saving long term effects. It reduces crime, participants are less likely to drop out of school, to become pregnant, increases chances to own a home and decrease chances of being incarcerated, Graue said.