Little more than eight months ago, the bungled rollout of the government’s Obamacare website,, touched off an avalanche of bad news for President Obama and his health care team. Now comes a new federal report that gives more details on the technical woes of the online  insurance exchange — problems that could result in enrollees getting subsidies that are too small or too big.

The inspector general’s report for the Department of Health and Human Services found that the online federal marketplace could not resolve nearly 90 percent (or 2.6 million) of its 2.9 million data “inconsistencies,” which include citizenship status, income, incarceration status, and Social Security numbers.

The IG conducted site visits and surveyed staffs for all 15 state-run online exchanges as well as for between January and March. Although the state Obamacare exchanges were more able to identify and resolve data inconsistencies, the federal government’s exchange could not determine the number of applicants who had at least one inconsistency, the report said.

Robert E. Moffit, a senior fellow at The Heritage Foundation, said the report highlights many of’s “back end” problems that likely will have future consequences.

“When the administration unveiled the website, it was plagued with front-end issues” such as page crashes and slow response times, said Moffit, who works in Heritage’s Center for Health Policy Studies. He added:

The administration worked diligently to resolve those issues, but has failed to get a handle on the back-end issues that deal with the heart of the Obamacare process: administering subsidies to eligible Obamacare enrollees to help lower their monthly health premiums.

Without a clear resolution on patient data such as citizenship or income, the federal health exchange set up by the Affordable Care Act could mistakenly overpay, underpay, or deny subsidies to eligible Americans, Moffit said.

That would be politically explosive if it became a widespread problem, especially if the miscalculated subsidy amount was from the government’s inaccurate data collection.

The IG report recommends that the Centers for Medicare and Medicaid Services, the agency within HHS that runs, make a public plan on how and by what date the federal exchange would resolve the discrepancies.