Q: I heard that a lot of people have had problems using the federal health insurance exchange Web site, HealthCare.gov. What’s going on?

A: In the first several days, many consumers hit a bottleneck when they tried to get onto the site and create accounts, a step required before they can shop for health insurance plans and go on to enroll. Administration officials have been quick to say that much of the problem was due to unexpectedly high traffic, reflecting the demand for coverage. This issue has been partly resolved.

But as insurers, consumers and health advocates have gotten deeper into the site, they have noticed other problems. They say the site sometimes gives inaccurate information about the federal tax credits that will help most people pay for a health plan. And it sometimes erroneously tells low-income people that they are not eligible for Medicaid. Separately, insurers have complained that they are getting confusing information about who has signed up, with the exchange generating data that suggest multiple enrollments and cancellations for the same person on the same day.

And it is too early to know how well the site will do on even more complex things, such as billing.

Calculator: How much will you pay for insurance?

That sounds complicated. Who built this thing, anyway?

There were 55 contractors, including CGI Federal, a unit of a Montreal-based company that has the biggest contract. QSSI, a Columbia venture, worked on the “data hub” that passes information back and forth between HealthCare.gov and other systems managed by the Social Security Administration, the Department of Homeland Security and other agencies. The oversight and system integration was done in-house by technical staffers at the Centers for Medicare & Medicaid Services rather than by a contractor experienced with managing large projects — which was unusual for an enterprise of this scale.

So the government can’t keep a Web site up. Why is this such a big deal? What is at stake?

One way of looking at this is that a messy beginning for the exchange, if the problems are fixed pretty soon, isn’t a big deal, because people who enroll by Dec. 15 will have health insurance coverage that begins Jan. 1. (That’s when the law says most people are supposed to be covered.) And this first year, the open-enrollment period lasts until March 31. So there is time. But no one knows when the problems will be fixed.

And there is another question: As people get frustrated trying to use the exchange — or simply hear that it is hard to use — will that affect their willingness to sign up? If people end up being deterred, that’s a problem for two reasons. One is the requirement that most Americans carry insurance. The other involves the mix of healthy and sick people who sign up; the only way the prices of the health plans in the exchange can be stable is if they attract enough people who are inexpensive to insure because they don’t need much medical care. But in an exchange that is tricky to use, it’s the sick, expensive-to-insure people who are likely to be the most motivated to persist until they have managed to sign up.

What is being done to fix the problems?

The Obama administration isn’t saying much about what exactly is wrong with the exchange, let alone what is being done to fix it. What officials are saying is that they have brought in an unspecified number of extra computer experts from various parts of the government and from private companies to work on the case. Some members of this expanded team, including several White House innovation fellows, are working out of temporary office space in Northern Virginia rented by CGI Federal, one of the major contractors that built the exchange.

Neither the White House nor the Department of Health and Human Services has made any predictions about when the Web site will be working well.

How much is this going to cost, and who is going to pay for it?

Health and Human Services officials have declined to say whether the government will pay for the fixes and upgrades or whether they have asked the contractors to absorb some or all of the costs.

These bugs get more expensive to fix over time. The rule of thumb in the industry is that if something can be fixed for $1 before a project’s launch, it will cost 100 times that after the launch.

Technical issues aside, can we tell how popular the insurance exchange is? How many people have enrolled?

The White House has said that it will not release enrollment figures until November but that about 476,000 shoppers have filed applications for insurance. These are people who have filled out personal information, such as where they live and their income, and may now be waiting to hear back from the federal government about which programs they might be qualified to use. They have taken the first step toward purchasing coverage but are not yet enrolled in plans.

I want to apply, but I keep encountering issues with the site and am frustrated. Should I continue to try to register online? Will I have time to complete my application?

There is no harm in waiting a few weeks to purchase a health insurance plan. Although the law calls for consumers to have coverage by Jan. 1, officials have said people won’t be penalized if they sign up for insurance by Feb. 15. After that, they will pay a fine for the months in which they remain uninsured. The 2014 open-enrollment period ends March 31, which is the last day consumers can buy coverage through the health insurance marketplaces.

People can also sign up by contacting a call center at 1-800-318-2596 or mailing in a paper application.

Sandhya Somashekhar ,
Amy Goldstein , Sarah Kliff
and Lena H. Sun