More than 250,000 Americans selected private health-insurance plans through Obamacare enrollment systems last month, better than twice as many as in October when the exchanges opened amid technology errors and outages.

Kathleen Sebelius, the U.S. health secretary, asked today for a formal investigation of what went wrong with the Oct. 1 debut and said she’s taking steps to prevent future failures. While the Obama administration said it’s optimistic about the improved performance of the online marketplaces, it remains far behind in the effort to meet the U.S. Congressional Budget Office’s projected enrollment of 7 million people by March 31.

All told, 364,682 people in two months selected an insurer using the federal and state exchanges created by the Patient Protection and Affordable Care Act, according to a government report today. An additional 803,077 were found eligible for state children’s health plans or Medicaid, the program for the poor being expanded in at least 26 states next year.

“We think we’re on track and we will reach the total that we thought because we’re only two-and-a-half months into a six- month open-enrollment period,” Mike Hash, the director of the office of health reform at the U.S. Department of Health and Human Services, said on a conference call with reporters.

An HHS memo dated Sept. 5, obtained by the House Ways and Means Committee, projected 1.2 million people would be enrolled in private insurance coverage by the end of November -- more than three times the actual number.

“We’re not exclusively focused on reaching a particular number,” Hash said later in the call. “What we’re focused on is reaching the millions of people who are looking for affordable health-care coverage.”

Repair Effort

The botched Oct. 1 debut of the exchanges prompted President Barack Obama to recruit Jeffrey Zients, scheduled to become his top economic adviser after Jan. 1, to oversee a “tech surge” to fix the flaws that initially prevented most people from easily using the marketplaces. The administration announced Dec. 1 that it had met its goals for repairs and that most customers would find the federal website working well.

About 110,000 people signed up in November from 36 states that rely on the federal enrollment system. That’s about four times the number of people who selected plans in October.

The improved performance has both major U.S. political parties shifting strategies, with Obama’s team preparing a January advertising blitz and wave of celebrity promotions, and Republican opponents in Congress highlighting examples of people who are paying more for insurance or losing access to their doctors.