As Sarah Kliff and I wrote in our overview of the health-care launch’s technical issues, the challenges right now can be grouped into three broad categories: problems with the consumer experience on the HealthCare.gov Web site, problems with the eligibility system, and problems with the hand-off to insurers.

The problems with the Web site are the difficulties consumers are facing when they try to log on and shop for insurance coverage. These problems — error messages, site timeouts, difficulty logging in to an account — make it hard for an individual to buy coverage through the marketplace. They are the reason why some people have made upward of 20 attempts at purchasing a plan. These are the problems that are being fixed fastest and that are the least serious.

The eligibility problems strike when consumers send in their information and the government’s computer systems tell them whether they’re eligible for Medicaid, health insurance subsidies or nothing at all. The system is returning incorrect data for many applicants — meaning they might be eligible for Medicaid and not know it, or they might think they have subsidies that will later be revoked.