WASHINGTON – The government on Friday named a UnitedHealth Group Inc. subsidiary as "general contractor" to oversee the troubled federal website designed to sign up Americans for health insurance under national health care reform.

Quality Software Services Inc., known as QSSI, will "oversee the entire operation" of Healthcare.gov, a government spokeswoman said.

The Maryland software company, acquired by Minnetonka-based UnitedHealth's Optum business unit in 2012, designed the website's data services hub, one of the functions that has worked well since the problem-plagued system went online Oct. 1.

QSSI now becomes responsible for prioritizing the site's worst problems and getting them fixed.

"They've done a good job already," said Julie Bataille, communications director for the Centers for Medicare & Medicaid Services (CMS), which oversees Healthcare.gov. "They are familiar with the project and have the skills and expertise to address these problems."

A one-sentence statement QSSI issued on Friday provided no details on how the company expects to attack issues that have delayed the ability of hundreds of thousands of Americans to get health insurance coverage.

"Working with CMS, QSSI will help monitor, assess, prioritize and manage the technical operations of healthcare.gov to enhance the consumer experience," the statement said.

People in 36 states will use the federal website to sign up for coverage because their states did not create exchanges like Minnesota's MNsure. Users of the federal site have complained of long wait times, dropped connections and lost data.

At a House Energy and Commerce Committee hearing Thursday, Optum Vice President Andy Slavitt, QSSI's boss, told members of Congress that even his attempt to establish an account on the website had failed.

Management consultant Jeff Zients, brought in by President Obama to troubleshoot the insurance sign-up system, said that in the first few days of the website's operation, very few people could create accounts, much less apply for insurance.

Now, with technical fixes and expanded computer power in place, 90 percent of those who try to create accounts succeed, Zients said. But the ability of people to actually complete an application for health insurance remains poor.

"Performance has been volatile," Zients said. "At points it was very low, with as few as three out of 10 users getting through the application process."

Obama and Secretary of Health and Human Services Kathleen Sebelius have both called the sign-up system's performance unacceptable.

Using a construction analogy, Zients said a team of experts has produced a "punch list" of dozens of items that must be repaired or retooled for the system to function properly. QSSI will review that list and decide the order in which fixes will occur.

Zients promised that the sign-up system "will work smoothly for the vast majority of users" by the end of November.

Government officials were unable to say how much more taxpayers will pay QSSI for its new responsibilities. Slavitt told the Energy and Commerce Committee that the company's current contract was for $85 million.

But a new study by Bloomberg Government, which factors in late additions to the website's contractors, puts QSSI's share at $155.3 million out of a total of more than $1 billion.

Jim Spencer • 202-383-6123