HealthCare.gov is working much better than it was at the start of October. But the woebegone federal website that must haul a system of affordable health coverage into place if the health care law is going to succeed has a long way to go and a short time to get there.

Down 60 percent of the time after the site’s Oct. 1 launch, Obama administration officials say HealthCare.gov is up more than 90 percent of the time now.

But Jeffrey Zients, the fix-it man knocking heads to repair the site’s technical problems, is out the door at the end of the month. He’s President Barack Obama’s choice to head the National Economic Council starting in January.

So what are the odds that an administration that says it neglected to exercise enough management oversight of the crucial information technology piece of a law will do a good job of finishing the work needed? Or that it will make sure the tech problems are resolved and the site functions well from now on?

There are tons of questions when it comes to HealthCare.gov. Here are a few answers.

1. It’s just a website — what’s the big fuss about the HealthCare.gov tech problems?

The health care law brought with it many things that no Congress likely will want to erase: free preventive benefits, better Medicare drug coverage, family coverage for young adults up to age 26, no lifetime caps on insurance payouts.

But in a very real way, HealthCare.gov is the heart of the Affordable Care Act. The health care law will go down in history if it fulfills its potential to move the United States close to universal coverage. But that won’t happen if HealthCare.gov can’t enroll the right mix of young, healthy Americans to offset the cost of insuring older, sicker ones.

2. How could they screw it up when they had three years to plan for the launch?

This White House is often stingy with information, so it’s hard to know exactly what went wrong. But the work required to stand up the law has been enormous. Republicans tried to squeeze off funding to get it going and weaponized every snippet of information about it. But the White House staff dug itself a bunker. Bottling up regulations until after the 2012 elections left less time for HealthCare.gov. Not sharing plans for the site meant its flaws couldn’t be fixed with outside help.

3. Who were the health tech experts in charge? Wasn’t the private sector supposed to play a big role?

Henry Chao? This midlevel Department of Health and Human Services bureaucrat helped the Bush administration muddle through its messy 2006 launch of the Medicare drug benefit. But the exchange website job required a CEO type with Obama’s ear to whom White House staff and HHS leaders would defer. Obama relied heavily on trusted political aides who skillfully negotiated the health care law through Congress and thought they could manage HealthCare.gov into being, too. Todd Park, a high-energy, talented tech entrepreneur was on the government payroll, but contractors CGI and QSSI reported to other government officials.

4. Weren’t there warnings signs that could have prevented this?

Many. Most telling were the administration’s vague replies when asked for more details about the planning and testing of HealthCare.gov.

Its message was: Don’t worry about the details; the site will be ready by Oct. 1. But Montana Democratic Sen. Max Baucus, a leader in negotiating the health law, almost pleaded with a Centers for Medicare and Medicaid Services official at a February hearing to keep him better informed. And Chao raised eyebrows at an insurance industry conference in March.

“I’m pretty nervous,” he said. “Let’s just make sure it’s not a third-world experience.”

Six months before the launch, McKinsey & Co. consultants told administration officials they had not set aside enough time for testing the whole system, according to documents released by the House Energy and Commerce Committee. The consultants said the site should be designed, built and tested sequentially after its requirements were defined — but it was built at the same time requirements were changing.

5. What’s working better now?

Like new car buyers, consumers weren’t ready to whip out their checkbooks on Oct. 1. First, they wanted to kick the tires, check out what plans they could buy and how much they cost. But few could even look through the showroom window. Consumers had to create accounts that required getting their identities verified online and got frozen screens and error messages.

Now, new pages pop up in less than a second, not eight seconds or longer. It’s easier to create accounts. A “See Plans Before I Apply” button permits window shopping without an account. And if site visitors have all their information ready, 80 percent of them can now enroll in a single sitting, up from just 30 percent in October, a federal official said.

7. What are biggest technical problems now and how fast will they be fixed?

Most are invisible to consumers — for now. These back-end problems include incomplete, inaccurate or duplicate enrollment data that HealthCare.gov sends each day in “834 forms” to insurers telling them who signed up for their plans. Insurers worry most about “ghost” files that vanish instead of being received by insurers.

About 30 percent of the website isn’t even built. Still missing is a tool to compare the enrollment lists of HealthCare.gov with those of insurers. Left also on the to-do list: a way to transmit federal subsidy payments to insurers and user fees from insurers to the feds. No one is saying when the fixes will be ready. And Web developers need to add a way to transfer payments in 2015 from insurers with healthier-than-average customers to insurers with sicker-than-average patients.

8. Could people enroll by the Dec. 23 deadline but be told by doctors or hospitals next year they don’t have insurance?

That is one of the biggest worries right now. CMS officials are advising consumers to check with their new insurers to confirm coverage, particularly if they haven’t received their insurance cards. No one wants a situation in which consumers try to get medical care and are turned away by a hospital or doctor’s staff or, if they do succeed in getting care, later learn that the treatments were not covered.

The timing is extremely tight. People have until Dec. 23 to enroll and until Dec. 31 to pay their premiums for coverage that’s supposed to start on Jan. 1.

9. If fewer people than expected are insured, doesn’t that mean the health care law is bound to fail?

The Congressional Budget Office estimated that 7 million people would enroll in the federal and state marketplaces by March 31, 2014. The CBO predicted another 9 million would sign up throughout 2014 for the low-income program Medicaid. So far, neither outcome is guaranteed, and the marketplace enrollment is likely to fall way short.

If enrollment isn’t as strong as predicted, insurers could jack up their premiums in 2015. If that happens, there may be fewer healthy people next fall willing to pay premiums that subsidize sicker people. That could lead to a cycle in which the pool of people buying coverage will become increasingly sick and costly to cover.

But that worst-case scenario overlooks a few points.

First, some analysts say the most crucial factor is not how many people sign up, but how healthy those enrollees are. Healthy people may not abandon the system, in part because federal subsidies will keep costs relatively reasonable for lower-income people, many of whom are young, and because the law requires most Americans to buy coverage.

Insurers may not want to hike premiums dramatically in 2015, because it’s in their interest to entice people to buy their products. And insurers have training wheels for the first three years, anyway, because the federal government is covering the costs of many of the sickest patients and capping insurers’ losses. So if the first year’s enrollment data aren’t impressive, it doesn’t necessarily mean the death of the program. But a Zients-like replacement is likely needed to get it in shape.