LANSING, Mich. -

State auditors are knocking Michigan's tax-free Renaissance Zones, saying commerce officials haven't come up with a way to measure the program's effectiveness.

A report released Wednesday says the state relies on reports from businesses and hasn't verified the number of new jobs or how much private money has been invested.

Businesses operating in Renaissance Zones are free of many local and state taxes.

They range from urban areas in the Lower Peninsula to remote, rural areas in the Upper Peninsula.

The audit estimates that tax breaks worth $820 million have been granted since 1997, mostly local taxes.

The state says more than 12,000 jobs have been created, but auditors say the number hasn't been independently verified.

The Michigan Economic Development Corp. is working on ways to judge the program's effectiveness.

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