3. Are the young people who are enrolling actually healthy? This one will be hard to answer, but it’s important. In the population as a whole, young adults tend to be healthier, and therefore less inclined to use lots of health care services, than their elders. But the characteristics of the 6 million or so folks who end up in the exchange population may not mirror the population as a whole. It’s entirely possible that the young adults who do end up signing up will be sicker, on average, than their peers. If so, that will complicate premium pricing down the road.

4. What are the sign-up totals, demographic breakdowns, and overall health of the individual state markets? The headline national numbers only tell part of the story. By the middle of this month, 13 states had exceeded initial enrollment projections, according to a count by Philip Klein of The Washington Examiner. But another 12 states were at less than half their projected sign-ups, and 24 were at less than two-thirds of sign-up expectations. What this means is that Obamacare is going to look very different depending on what state you live in. Some states will meet or beat enrollment expectations and presumably end up with viable insurance markets in the process. But others will have low enrollment totals and bad demographic mixes, and are likely to face higher premiums and fewer plan choices as a result.