A Freddie Mac study concluding that far more black people have bad credit than white people, even when both have the same incomes, has come under attack in Congress, and some experts have questioned whether it oversimplifies a complex issue.

The study's authors defended their conclusions but said they probably should have chosen language other than "bad credit" or "good credit" because they were trying to say whether people had trouble paying their bills.

The study of 12,000 Americans with incomes up to $75,000 received wide media coverage when it was released last month by Freddie Mac, a federally chartered agency that provides capital for mortgage lending. It is one part of a new program to teach minorities how to improve their credit, in partnership with the NAACP, the National Urban League and five historically black colleges, including Howard University.

The researchers, relying on data from credit reports, designated people as having "bad credit" if they had two bills overdue more than 30 days in the past two years, one bill more than 90 days late, a lien, a judgment or a bankruptcy. Their data showed that a higher percentage of African Americans with incomes of $65,000 to $75,000 had "bad credit" than whites with incomes below $25,000.

The criteria they chose, researchers said in an interview, do not reflect the full range of what credit agencies look at, which includes life circumstances and the borrower's long-term repayment pattern.

"This issue is not that this would get you denied a loan, but this reflects empirical evidence of the difficulty people have making their payments," said Peter Zorn, director of financial strategy and policy analysis for Freddie Mac. The quotation marks around the words "bad credit" and "good credit" "were supposed to signal that it was not pejorative," he said.

But U.S. Rep. Maxine Waters (D-Calif.) said the report is flawed on a number of grounds. She was joined at a news conference Thursday by U.S. Rep. Gregory Meeks (D-N.Y.), and representatives of two advocacy groups, D.C. ACORN and the National Fair Housing Alliance.

Waters, a member of the Banking and Financial Services Committee, said the Freddie Mac report concluded that minorities were responsible for their credit problems, which runs counter to a large body of research showing widespread racial discrimination in the lending and credit industries.

"In other words," she said, "we are a credit risk because no matter how much money we make, we are also too stupid and undisciplined to know how to spend, plan and save."

Freddie Mac, she said, omitted factors "that clearly demonstrate that African Americans and whites are not similarly situated in this society and especially not in the world of credit."

Freddie Mac and its partners in the credit study issued a statement responding to Waters, saying they also are concerned about discrimination issues. Officials from two of the colleges defended the study.

"It's a truth," said David Swinton, president of Benedict College in South Carolina. "Why should anybody be upset at a truth?"

However, Antoine Garibaldi, provost at Howard University, said he is concerned that some people might wrongly draw the conclusion that African Americans cannot manage their money, partly because the study, which will include more detailed statistical information, has not been completed.

"We probably could have waited in order to have more of the information before the study was released," he said.

Economist Andrew F. Brimmer, the former head of the D.C. financial control board who has served on numerous corporate and banking boards, said he has sent for a copy of the report because he has questions about its methodology.

"I was concerned because not enough was done to explain the context and the setting," Brimmer said in an interview.

"I did not recognize from the newspaper stories the risk assessment and lending practices with which I was familiar. Therefore, the summary provided the grounds for what I believe are, if not misleading, not fully clarified expositions."

Freddie Mac, Fannie Mae and other lending institutions have been under growing pressure to expand their lending to minorities, and Brimmer said he is concerned that the new study could give lenders an excuse to pull back.

Margaret Simms, vice president for research at the Joint Center for Political and Economic Studies, said she is concerned that the headline-grabbing element in the report--that even when blacks have incomes equal to whites, they still are more likely to have "bad credit"--may not reflect reality.

People can have the same income and vastly different household circumstances--a recent loss of employment or a larger family to support, she said.

"You take people with the same income but one group has worse credit, and that's presented [in the report] without taking account of things that might contribute to the drain on their resources," she said.