Any expansion of Indiana's already ambitious school voucher program may have to wait after senators pushed for more information Wednesday to determine the effects of the fledgling program.

Sens. Luke Kenley, R-Noblesville, and Earline Rogers, D-Gary, said they were concerned that too little information was available on the state's voucher program — which is barely a year old — to merit an expansion.

"This is a pretty, almost, cataclysmic change in the education system," Kenley said as the bill was debated by a Senate education committee. "I wonder if this would make sense to give it a rest for some time, say five years, and study it."

House Republicans advanced a multi-faceted plan to expand the voucher program last month that includes raising the maximum amount of each voucher to $5,500, raising the income eligibility limits for certain families and allowing children entering kindergarten to forgo a one-year stay in a public school.

On Wednesday, Rogers pressed a lobbyist for Gov. Mike Pence, who supports the expansion, what data he had to support his position. He pointed to increasing enrollment in the voucher program, but Rogers, a retired teacher, said she needed more.

"Maybe we need to wait and find out what happened to those students before increasing their numbers," she said.

The legislation also establishes a state matching program to encourage private donations to school choice groups that would then be used to send children to preschool.

But the voucher expansion has drawn the most protest, though not yet to the scale of the five-week walkout by House Democrats during the 2011 battle over right-to-work legislation. Voucher supporters and private school leaders rallied at the Statehouse last week, while public school officials and teachers packed the halls during a counter-rally Tuesday.

House Education Committee Chairman Bob Behning, R-Indianapolis, told members of the Senate Education and Career Development Committee that vouchers were needed to give Indiana more education options.

"What we're doing is providing more choices," said Behning, author of this year's voucher bill.

Kenley grilled Behning through the opening of the hearing, saying the provision that would allow children entering kindergarten to skip the one-year stay in a public school violated an agreement that won the votes needed to pass the voucher bill two years ago.

The measure won easy approval in the House, where it was backed by House Speaker Brian Bosma, R-Indianapolis, and a Republican supermajority. But Senate Republicans, including Senate Education Chairman Dennis Kruse, R-Auburn, have urged caution in embracing any expansion.

Kenley, who also chairs the Senate Appropriations Committee, could have a final say on the expansion this session if the bill is sent to his committee for a cost evaluation.