Three recent congressional hearings have renewed attention to an age-old problem in the government: accountability.

It was part of the subtext of last week's hearings on "diploma mills" -- businesses that sell academic credentials or require little academic work.

Investigators from the General Accounting Office testified that they had found 28 employees who listed bogus degrees in a survey of eight agencies. The investigators also learned from three unaccredited schools that they had 463 federal employees (257 from the Defense Department) enrolled as students. In the GAO snapshot, federal agencies paid nearly $170,000 in tuition to unaccredited schools.

For example, the GAO investigators said they found three managers at the National Nuclear Security Administration who hold degrees from unaccredited colleges. One of the managers told investigators that he did not attend any classes or take any tests and received his master's degree after paying $5,000. In talking to investigators, he called the degree a "joke."

The GAO investigation was sponsored by Rep. Thomas M. Davis III (R-Va.) and Sen. Susan Collins (R-Maine).

Collins, who chaired the hearing, said she is concerned "that federal officials who hold high-ranking positions, and security clearances in some cases, have degrees from diploma mills. It calls into question their qualifications and abilities to do their jobs."

In his remarks, Davis said, "Fake degrees have no place or value in the federal workplace."

Accountability also was in play at a House hearing last week. Rep. James C. Greenwood (R-Pa.) and other House members renewed criticism of the National Institutes of Health, where some scientists work on the side for drug, biotech and other companies. The deals have raised concerns about whether those federal employees are truly paying attention to their jobs when their consulting arrangements are worth hundreds of thousands of dollars and, in some cases, have provided potentially valuable stock options.

The third hearing, in late April, focused on a continuing problem: abuse of government credit cards by employees. An update prepared by the GAO found employees bought $400 briefcases, $224 leather backpacks, a $500 radio, leather bomber jackets, ski clothing, sunglasses and a mounted deer head. (Earlier audits found that employees had used the credit cards for adult entertainment, jewelry and cruises.)

In most of these cases, officials have been working to determine what kind of agency response is appropriate.

For example, at the National Nuclear Security Administration, which maintains the nation's nuclear weapons stockpile, spokesman Bryan Wilkes said the agency reviewed the degrees at issue and in each case "found out that they were not preconditions for their employment." He added, "In each case, the person did not use the degree to promote themselves and try to better their chances of getting the position."

At the NIH, officials have said they are taking steps to ban outside consulting by high-ranking scientists who play key roles in grant-making decisions.

Agencies also have tightened up credit card use and disciplined some employees. Still, GAO found in one of its reviews that 94 of 120 Defense employees faced no disciplinary action because of improper credit card charges.

Holding people accountable is not easy, said Robert D. Behn, author of "Rethinking Democratic Accountability" and a teacher at Harvard's Kennedy School of Government.

Government has an obligation to hold employees accountable, but accountability also requires that government make its expectations clear to employees, he said.

"In the credit card thing, your sort of basic, common sense, smell test is clear. We all know what the rules are," Behn said.

But employee expectations in other areas -- such as listing bogus degrees on resumes -- are a different matter, Behn suggested. "What has the federal government said to folks about this?" he asked. "What is the level of expectation? You can't hold me accountable for anything until the expectations are clear to me."

In general, he said, organizations like to deal with accountability issues at the lowest level, "where somebody didn't pass the 'what-were-they-thinking test.' " But Behn said that same test can be applied up the line to senior officials: "What were they thinking when they didn't make expectations clear?"