To prevail in court, "persistent documentation is crucial" for contractors, the CFMA study recommends. "Our review of cases indicates that many construction firms lose their appeals because of a lack of adequate evidence regarding the basis of their claims/defenses."

A case cited in the study in which documentation paid off involves Columbia Construction Co., which the U.S. General Services Administration (GSA) hired to modernize an Internal Revenue Service complex in Andover, Mass.

Columbia suddenly found itself in a tight spot when GSA insisted that cables for a new security system be "concealed or in conduit." That was a major change from the initial contract, which called for the cables to be installed in cable trays under the raised access flooring system and above the drop ceilings.

But Columbia walked away with the compensation it had sought—$491,450—in part due to the fact it had the documentation to show the original installation plan agreed upon by GSA.

For contractors in the field, "persistent documentation" can be as simple as creating an email trail, Basu says. Contractors need to clarify on a regular basis with the government agency what has been agreed upon.

Just simply hashing things out over the phone leaves too much open to interpretations. Among other things the contractor should do is to follow up a phone conversation with an email reiterating what was said and the agreed plan of action, Basu says.

Winning Record

Contractors had a winning record in legal showdowns with the GSA, either winning outright or winning a split decision in the majority of cases, according to the CFMA study.

Documentation isn't always enough.

Rockville, Md.-based Grunley Construction Co. filed a claim for $758,000 against the Architect of the Capitol over work it performed fabricating and replacing windows on the U.S. Supreme Court building. The firm's subcontractor "was required to redesign" windows and window trims because, claimed Grunley, the trapezoidal shape of the windows differed from what appeared on the initial drawings. But the contract appeals board said the errors were minor and didn't rise to the level of different site conditions.

But government agencies were more likely to prevail in disputes over infrastructure projects with more than $18.3 million at stake.

One key reason for this strong government win record in bigger disputes is that the U.S. Army Corps of Engineers controls many of these larger infrastructure contracts. Army engineers have proven to be the most formidable court opponents that contractors are likely to come up against.

Overall, the Corps won 21 cases outright, compared to just four decisions that favored contractors, the CFMA study observes. The meticulous engineering mind-set of the Army's bridge and levee builders may make them formidable opponents in court, Robinson notes.

"These are engineers. The Army Corps of Engineers is all about engineering," he says. "There is great specificity. If contractors are going to pursue claims against that agency, they are going  to come up against all of that retail specificity."