LANSING — Debate is intensifying over plans to expand a $200 million tax incentive program for big businesses that proponents say has helped Michigan land planned investments, but not yet created a single job.

The state has so far committed $168.3 million in future tax captures to five firms under the “Good Jobs For Michigan” program, which launched in 2017 but is set to expire at the end of the year. Qualifying companies have promised to create a combined 8,104 jobs in exchange for an income tax payback that would amount to more than $20,500 per new employee.

Fiat Chrysler Automotive North America, which plans to build Detroit’s first auto assembly plant in nearly three decades and expand its Warren Truck Assembly Plant, could earn up to a $105 million incentive. And economic development leaders say other planned projects could depend on legislation that would lift the program cap to $500 million through 2024.

“There are currently six other projects in our pipeline that would create an estimated 6,830 new jobs and lead to an additional $3.4 billion in private investment,” Jeff Mason, President and CEO of the Michigan Economic Development Corporation, told lawmakers in committee.

The push for a Good Jobs extension comes at the same time as out-of-state lobbyists are urging Michigan lawmakers to go what they call “big game” hunting, by passing a sales tax exemption to lure the kind of standalone cloud storage data centers used by tech giants like Facebook and Google.

Switch data center, meanwhile, is asking the state for additional tax breaks four years after lawmakers adopted a $20 million sales tax exemption to help the Nevada-based tech firm turn a pyramid-shaped building into a server farm in suburban Grand Rapids.

Bipartisan bill sponsors contend their new or expanded incentive proposals would help drive continued economic growth in Michigan and position the state to compete against neighbors.

But policymakers lack objective data to gauge the effectiveness of existing programs. Legislators last year created a law requiring external evaluations of at least 16 tax state incentives, but they did not provide any funding to pay for the reviews.

"There are significant costs associated with this, and without the funding, this is stuck in neutral for now," budget department spokesman Kurt Weiss told Bridge Magazine.

The Whitmer administration is preparing to ask the Legislature for $2 million to begin implementing the incentive evaluation law, but that "would not be nearly enough funding for the long term," Weiss said.

Many researchers are skeptical about the impact of business incentives, which siphon tax revenue from the government that could be used to fix roads and schools – amenities that themselves lure businesses to the state.

“Schools in particular can really suffer,” said Nathan Jensen, a University of Texas-Austin professor and co-author of "Incentives to Pander," a book that describes incentives as an economically inefficient way for politicians to claim victories.

"If Amazon moves 20,000 workers into a city, it's not all benefits. There's costs associated with it, and the most obvious one is schools. You're adding more students and you have less revenues in the system."

‘But for’ what?

A bipartisan proposal sponsored by Republican Sen. Ken Horn of Frankenmuth and approved last week by his Economic and Small Business Committee would extend and expand the Good Jobs program, which allows big job creators to keep income tax revenue generated by their new employees for up to a decade.

Income taxes are used to support an array of state services. Nearly 25 percent of all collections go to the School Aid Fund ($2.8 billion last fiscal year). Most of the rest goes into a discretionary general fund, but a 2015 road funding law requires an annual diversion that will climb to $600 million by 2021.

Any tax revenue given back to firms would not exist without the Good Jobs program, Horn argued in committee, echoing a common “but for” argument often used by business incentive proponents.

“They wouldn’t be here but for some of the incentives,” Horn said of qualifying companies, which have announced plans for private investments totalling more than $5 billion.

“Good Jobs has never been a silver bullet. It’s just one more puzzle piece in this big jigsaw puzzle we have as an economy in Michigan,” he said.