The GAO upheld Boeing’s protest of the Defense Department’s 2008 award to replace the Air Force’s refueling tanker to the team of EADS North America and Northrop Grumman. Boeing ultimately won the contract earlier this year. (Paul J. Richards/AFP via Getty Images)

After several years of double-digit growth in the number of complaints filed to protest contract awards, the Government Accountability Office reported last week that the claims have leveled off.

As the government contracting market has become more competitive, the number of protests has surged. Between fiscal 2007 and 2011, the figure jumped dramatically from 1,411 to 2,353.

Government contracting attorneys generally have cited the challenging environment as well as the government’s increased use of contract vehicles, which require that contractors win a spot on the program to be eligible for task orders. If they lose, contractors worry they’ll be shut out of work for an extended time period.

But that dramatic growth is ebbing, according to the latest GAO report on its bid protest statistics. In fiscal 2011, the 2,353 protests filed reflected a 2 percent increase from 2,299 the year before.

The percentage of protests upheld by the GAO declined, down to 16 percent from 19 percent in 2010. In 2006, the number of cases supported by GAO hit a recent high of 29 percent.

Still, the effectiveness rate — or the percentage of cases in which the protester received some form of relief, for example by seeing the agency rework or restart the program — stayed steady at 42 percent.

Protest experts said the latest numbers don’t necessarily mean contractors are shying away from the protest process.

“I think we expected at some point, [the numbers] would begin to flatten out,” said Michael R. Golden, an attorney with Pepper Hamilton’s government contracts practice. “But we just have to wait and see if this becomes a trend, if it flattens and even goes down.”

Golden was previously the GAO’s managing associate general counsel for procurement law and spent more than 30 years at the agency.

He said a shrinking budget and a reduced number of contracts could increase the number of protests, but, on the other hand, contractors under financial pressure might feel less able to spend money on protesting.

Marcia G. Madsen, a partner at Mayer Brown and the former chair of a congressionally mandated panel that reviewed the federal procurement system from 2005 to 2007, said the numbers go up and down, but contractors still take protesting very seriously.

“Companies do think really hard about filing protests,” she said. “That’s a big decision.”