Topeka ? Three years ago, Kansas lawmakers enacted sweeping, historic cuts in state income taxes, eliminating taxes entirely for certain kinds of business owners.

It was Republican Gov. Sam Brownback’s signature policy initiative — an experiment, he once called it, in supply-side economics — that he said would spur the Kansas economy, creating new business activity and job growth.

Now, with state government facing a budget hole estimated at more than $422 million and signs showing the Kansas economy not performing significantly better than the national economy, the debate over the wisdom of those tax cuts is starting to heat up.

That was evident Thursday when the House Taxation Committee received its briefing on the latest consensus revenue estimates.

Those estimates, which were released April 20, said the state now expects to collect about $98 million less in the next fiscal year than previously thought. And the news got mildly worse Thursday when the Department of Revenue reported that tax collections for the month of April came in $4.4 million below estimates for the month, due mainly to lower-than-expected corporate income tax receipts.

“We know what’s been going on with employment and its growth,” said Chris Courtright, senior tax analyst for the Legislature’s nonpartisan Research Department. “The great question is, to what extent would some of that growth have been there anyway, or what part of it would have been stimulated as a result of the new tax law changes. And to my knowledge, I don’t think anyone has any specific numbers for you on that.”

Much of the focus now is on the complete exemption from state taxes for certain nonwage, or “pass-through,” income from certain kinds of business operations. That’s business income from a sole proprietorship, limited partnership or other type of corporation that simply passes through to the business owners and is normally taxed as personal income instead of business income.

Initially, state officials thought the pass-through exemption would eliminate taxes for about 190,000 small businesses. But the Department of Revenue now says about 330,000 business owners are claiming the exemption.

Those include many farms and small businesses that people operate out of their homes, as well as certain law firms, medical practices and other businesses that organize as limited partnerships, limited liability corporations or “subchapter S corporations,” which pass all of their corporate income, losses, deductions and credits to their shareholders.

Richard Cram, director of policy and research for the Department of Revenue, said an analysis of 2014 tax filings showed that 8,800 new business entities were created last year, based on the number of tax filers who claimed exemptions for certain nonwage income that is no longer taxed by the state.

But Rep. Tom Sawyer, of Wichita, the ranking Democrat on the panel, said it was hard to tell whether that number was exceptional or below average.

“You think about that number, there’s always going to be new businesses coming on, old businesses coming off,” Sawyer said. “You’re going to have to have 10,000 or 15,000 new each year just to sustain that kind of number. So if we only have 8,800 total, it sounds like we’re lagging behind a normal year, not above a normal year.”

As lawmakers now look for new revenues to fill the state’s budget hole, even some Republicans who supported the tax cuts in 2012 now say they’re willing to consider revisiting some of them, especially the pass-through exemption, which they say went further than they were led to believe three years ago.

Sen. Jim Denning, R-Overland Park, has said he intends to introduce a bill that would reimpose taxes on the first $118,500 of business owner income. And Rep. Marvin Kleeb, also of Overland Park, who chairs the House tax panel, has said some adjustment to the pass-through income exemption will at least be considered as a final tax package is put together.

But other Republicans are more reluctant to reconsider changing course on income taxes.

“What worries me is, by raising taxes do you still think that Kansas will be a leading place for growth where people will want to come and raise their family, retire and start a business,” said Rep. Ken Corbet, R-Topeka, a member of the House tax panel.

Rep. Kasha Kelley, R-Arkansas City, said she wants to see more data on business creation in Kansas before the committee considers rolling back any of the tax cuts.

“It’s very tough to make the decisions that we’re going to be making right now because we aren’t so far out from tax plan of 2012, but obviously there’s something there that’s tilling the soil,” Kelley said.

The Department of Revenue said it would try to have more comprehensive information for the committee’s next meeting on Monday.