The findings are similar to those of a growing list of inspections, audits and investigations that have concluded that the program to rebuild Iraq has often fallen short for the most mundane of reasons: poorly written contracts, ineffective or nonexistent oversight, needless project delays and egregiously poor construction practices.

“This report is the latest chapter in a long, sad and expensive tale about how contracting in Iraq was more about shoveling money out the door than actually getting real results on the ground,” said Stephen Ellis, a vice president at Taxpayers for Common Sense in Washington.

“These contracts were to design and build important items for oil infrastructure, hospitals and education, but in some cases more than half of the money padded corporate coffers instead,” he said.

Although the federal report places much of the burden for the charges squarely on the shoulders of United States officials in Baghdad, the findings varied widely over a sampling of contracts examined by auditors, from a low of under 20 percent for some companies to a high of over 55 percent.

One oil contract awarded to a joint venture between Parsons, an American company, and Worley, from Australia, had overhead costs of at least 43 percent, the report found. One contract held by Parsons alone to build hospitals and prisons had overhead of at least 35 percent; in another, it was 17 percent.

The lowest figure was found for certain contracts won by Lucent, at 11 percent, but the report indicates that substantial portions of the overhead in those cases could not be determined.

The report did not explain why KBR’s overhead costs on those contracts  the contracts totaled about $296 million  were more than 10 percent higher than those at the other companies audited. Despite past criticism of KBR, the Army, which administers those contracts, has generally agreed to pay most of the costs claimed by the company.