For example, in his opening statement, Rep. Tim Murphy, R-Pa., called the federal exchanges the “ultimate 'cash for clunkers' program.”

Rep. Fred Upton, R-Mich., chairman of the panel, repeatedly sought to elicit from the contractors whether the Department of Health and Human Services (HHS), the parent agency, and the Centers for Medicare and Medicaid Services (CMS), which administers PPACA, approved launching of the site Oct. 1 even though the contractors expressed concern to them that the exchanges were not ready for prime time.

Upton said that in hearings held before Oct. 1, “Top administration officials and lead contractors appeared before this committee, looked us in the eye and assured us repeatedly that everything was 'on track.'” Upton said. “Except that it wasn't, as we now know all too well.

So why did they assure us the website would work? Did they not know? Or did they not disclose? That's what we are looking to find out, with the contractors today, and with Secretary [Kathleen] Sebelius next week.”

Rep. Marsha Blackburn, R-Tenn., a ranking Republican on the committee and an outspoken critic of Obamacare, said in her opening statement that, “These past three weeks of exchange messiness demonstrate that no member of this body should be a blind cheerleader for the Affordable Care Act and ignore the problems before their very eyes.” She later raised the issue of whether the site complied with federal health privacy laws.

Republicans did win acknowledgement during questioning of the vendors that some of the source code for the exchange is being changed, although it is unclear if that is being done daily or regularly. Vendors also acknowledged that testing of the integrated system, put together by a number of vendors, was not done until the last minute, for example, the last several weeks before launching, although ideally, the vendors testified, that such a complex site would undergo months of intensive testing.

Rep. Michael Burgess, R-Texas, a doctor and outspoken opponent of PPACA, is founder and chairman of the Congressional Health Care Caucus. He asked the contractors, “When should we have comfort [that the federal site will be working]?” Texas, which has the largest number of people without health care insurance in the country, has adamantly refused to participate in the exchanges and also in the expanded Medicaid program, which launches next month.

Told by the contractors that CMS is responsible for getting the federal exchange in shape, Burgess said, “No one believes things will be fixed with answers like this.”

Officials of CGI and Optum/QSSI, two of the key vendors, admitted that “months of end-to-end testing,” not the days or last two weeks before launching, is the industry standard for the complex website being used to solicit applications for insurance policies purchased to comply with PPACA.

But Democrats on the panel defended the Obama administration.

For example, Rep. Jan Schakowsky, D-Ill., said, “Let's work together to fix it, not mix it — as we did on Medicare Part D under [President George W.] Bush.”

Rep. Henry Waxman, D-Calif., outspoken ranking minority member of the committee and its former chairman, criticized the Republicans for convening the hearing. He said Republicans “have not shown us that they are trying to make this law work so far.”

Waxman called PPACA “an enormous success” even as he admitted it has “a poorly designed website.”

He said that Americans have already saved thousands of dollars because of the law, although he agreed early performance of the website has caused “notable frustration and anxiety.”

Rep. Frank Pallone, D-N.J., the top Democrat on the panel's health subcommittee, called it a “monkey court.” He said the Republican majority has “a dishonest interest in the website's flaws. Republicans don't have clean hands coming here. Do you really care? I don't think so.

“Here we go again, another cynical effort by the Republicans to delay, defund or ultimately repeal the Affordable Care Act,” Pallone said. “I'd like to think this hearing is above board and legitimate, but it's not.”

The contractors responded by saying that they did share risks and concerns with CMS about the viability of the federal exchange system, but that CMS ultimately decided to move forward. Cheryl Campbell, senior vice president of CGI Federal, the lead contractor, told Upton that CGI is not supposed to share its opinion on whether to go live or not.

But, in their testimony, the contractors defended their work. “In systems this complex, it is not unusual to discover problems that need to be addressed once the software goes into a live production environment,” Campbell said.

She added that, “This is true regardless of the level of formal end-to-end performance testing — no amount of testing within reasonable time limits can adequately replicate a live environment of this nature.”

She also said that another contractor was responsible for the technology that allowed users to create new accounts and which caused the initial bottleneck issues on the site.

Still, Campbell said, CGI is responsible for some of the problems, too.

“Now, as more and more users have been able to proceed to the (exchange) over the past several days, more individuals have enrolled in qualified insurance plans,” Campbell said. “However, the increased number of transactions in the (exchange) have caused system performance issues (such as slow response times or data assurance issues) that now need to be addressed through tuning, optimization and application improvements.”

Campbell blames initial problems on the “enterprise identity management” function known as EIDM that serves as the entry portal to the website. The EIDM tool was designed by Optum. Campbell said it “created a bottleneck that prevented the vast majority of users from accessing” the federal exchange website when it opened.

But, in his testimony, Andrew Slavitt of Optum, which designed the EIDM tool, said that an unexpected high volume of people registered at the start and overwhelmed the entry portal and other aspects of the website. “After the launch, Healthcare.gov was inundated by many more consumers than anticipated,” Slavitt said. “Many of the critical components developed by these multiple vendors were overwhelmed.

Slavitt blamed the government. “It appears that one of the reasons for the high concurrent volume at the registration system was a late decision requiring consumers to register for an account before they could browse for insurance products.”

He said the EIDM tool is only one piece of the federal marketplace's registration and access management system, which involves multiple vendors and pieces of technology. “Tools developed by other vendors handle critical functions such as the user interface, the e-mail that is sent to the user to confirm registration, the link that the user clicks on to activate the account, and the web page the user lands on,” Slavitt said.

He also said that by Oct. 8, “even at high levels of registration, the EIDM tool was processing those volumes at error rates close to zero, and continues to do so.” As a result of this work, the EIDM tool is keeping pace with demand, Slavitt said.

Lynn Spellecy, representing a third contractor, Equifax Workplace Solutions, said its role was providing “real time verification of income and employment” information submitted by applicants has worked properly.”

Equifax conducted “multiple load and stress tests” that showed it could process up to 120,000 verification requests per hour or more, which it estimated as more than any peak period would demand, Spellecy's testimony says.

The hearing was convened as the White House and the HHS acknowledged major problems with the site, and disclosed that they are bringing in outside resources to deal with the difficulties for consumers and insurers.