Continued from page 1

In its place, the GOP substituted their own analysis from the House Budget Committee that said the Obama plan actually carries a total price tag of $2.6 trillion and will add $701 billion to the deficit in its first 10 years.

“This health care bill will explode the deficit when you look at this thing honestly,” said new House Budget Committee Chairman Paul D. Ryan, Wisconsin Republican.

Mr. Penner and Josh Gordon, policy director at the nonpartisan Concord Coalition, said criticism aimed at the latest CBO report is “misplaced” because the group never hides the fact that its estimates carry uncertainties.

“We firmly believe the CBO has been quite correct in nearly everything they’ve said about health care,” Mr. Gordon said. “They’ve not only put specific estimates as they’re supposed to, but many times they’ve indicated where the uncertainty lies in their analysis and how uncertain that analysis actually is.”

In one example, CBO researchers said that for the health care law to reduce the deficit, Congress will have to allow deep cuts to existing medical programs — something that CBO warned could be unrealistic.

The dispute over the CBO forecast marked one of the first major public relations spats between the new Republican majority in the House and the returning Democratic majority in the Senate, and it threw a kink in the GOP’s plans to fulfill their campaign pledge to repeal the law.

It also provided Democrats with an early opportunity to cast their legislative counterparts as hypocrites for violating their promise to rein in deficits and for ignoring reports that don’t suit their political agenda.

“To show how misguided the new House Republicans are, for a long, long time, anything that was done that had any money connected with it had to have a CBO score,” said Senate Majority Leader Harry Reid, Nevada Democrat. “They rejected that. They said no longer are we going to be bound by that.”

Despite the flare-up over the CBO, Mr. Ryan and Sen. Kent Conrad, the Democratic chairman of the Senate Budget Committee, have made it clear that they appreciate the work of the CBO and the performance of its director, Doug Elmendorf.

House Speaker John A. Boehner’s office also defended the CBO. “The Democratic leadership in the last Congress rigged the score by using budget gimmicks in the text they gave CBO,” said Michael Steel, Mr. Boehner’s spokesman. “That is not CBO’s fault.”

For now, though the CBO has taken shots, there is no obvious alternative to relying on its scores.

“It is easier to attack CBO because [they] can’t defend themselves and when numbers are inconvenient,” Mr. Gordon said. “If things aren’t going well with your referee, you try to deflect some of the attention by attacking the ref instead of worrying what is happening on the field.”