Size matters to the federal government, but defining size is no small matter.

At stake are billions of dollars in government contracts and loan guarantees, along with the survival of the businesses that depend on them.

The U.S. Small Business Administration held a public hearing Tuesday in Denver, one of 11 cities it is touring, on revamping its size standards.

The SBA defines "small" across more than a thousand industry classifications, juggles 37 size levels and measures size in terms of employees and revenues, said Gary Jackson, assistant administrator of the SBA's Office of Size Standards.

It could be another two years before a new, more simplified set of standards comes into place, he said.

"Everything is on the table," Jackson said.

The federal government must direct 23 percent of its procurement dollars to small businesses, which also have access to government guaranteed loans.

But SBA critic Lloyd Chapman, president of the American Small Business League, argues corporate giants siphon off billions of contract dollars each year set aside for small businesses.

A study last September from the Center for Public Integrity found that 30 percent of defense contract dollars reportedly going to small and minority businesses actually ended up in the hands of top defense contractors, he said.

"They are able to gobble up the opportunities that should be going to small business," testified Lloyd Lovell, head of LFL International, a small Denver construction firm.

That most often occurs when big companies acquire small businesses and keep their contracts, which can stretch for 20 years or more.