How to Tell When Someone's Misleading You About Obamacare

Everyone has an enrollment statistic they want to avoid, but it's all part of the same puzzle.

The hottest trend in Obamacare analysis is to wave off inconvenient statistics, claiming this or that metric "doesn't matter" if you really want to understand what's going on.

Don't listen to anyone who tells you this.

Every metric out there right now matters — just not in isolation.

The total number of sign-ups — 7.1 million — is a real and important number, despite critics' best efforts to rationalize it away. But the factors the White House would rather ignore — like the number of people who haven't paid their premiums — are also real and important numbers.

The Affordable Care Act is complicated, and trying to get an honest handle on the state of enrollment requires wading through an ocean of competing statistics. Unfortunately, that makes it easy for partisans to cherry-pick the numbers that work best for them (and for honest people just making a point to get a little hyperbolic).

There was a time, in October and November, when the only thing we could learn from enrollment data was that HealthCare.gov didn't work, which we already knew.

But that time has passed. Open enrollment is over. We have real data. And the fact is that no one metric tells the whole story of Obamacare enrollment — and no metric can be tossed aside as irrelevant.

Overall enrollment matters. The White House tried to get away from this number when it was low, insisting that there was no ultimate goal for enrollment. Now, it's Republicans — who had no qualms relying on the enrollment numbers when they were low — accusing the administration of "cooking the books."

Roughly 7.1 million people have selected an insurance plan through Obamacare's exchanges. That is important because the whole point of the Affordable Care Act is to cover millions of people. Whether that's happening is arguably the most important question about the law's success. There are important things this number doesn't tell us, but one very important thing it does.

The holes in the enrollment data also matter. Critics would have you believe they are all that matters, and that once they're filled, the 7.1 million figure will crumble and the law will un-pass the milestones it has already cleared. That's not likely — but these adjustments are still important.

We don't know how many people have paid their first premium — the final step to actually having coverage. The best estimates available now suggest it's about 80 to 85 percent. If that holds, the 7.1 million sign-ups will translate into about 6 million actual enrollees, give or take. Lower than what the administration has said? Yes. Low enough to destabilize the law or move it back across the threshold of first-year success? No. Six million would still meet the Congressional Budget Office's revised expectations for exchange enrollment, taking the HealthCare.gov debacle into account.

(And yes, CBO's estimates for enrollment very much matter.)

The number of previously uninsured people also matters. The point of the law wasn't just to cover millions of people, but to reduce the number of uninsured by millions of people. Some surveys suggest exchange enrollment is mostly people who already had coverage, but those data came before the last-minute sign-up surge.

The mix of healthy and sick matters. Whether premiums go up in 2015 depends mostly on the mix of healthy versus sick enrollees in each state, not the total number. Both sides have tried to turn the focus to this standard instead of overall enrollment (Democrats when the overall total was low and no one knew the risk mix, Republicans when enrollment picked up and the risk mix didn't look so hot). It is a bigger question when evaluating premiums and the odds of survival, but an exchange with only 50 people, even if they're all healthy, wouldn't be a successful exchange.

So, the ratio of healthy people is pretty important, but guess what? No one knows how many healthy people are signing up.

The mix of young and old enrollees matters. Because insurers don't know their customers' health status until people start filing claims, they use age as a stand-in. A young person is assumed to be healthier than someone older. That assumption isn't perfect, and some policy experts push back against the focus on age because age itself isn't terribly important. They're right, it's not, but it's the best tool we have to evaluate something that is important.

And that's what most of this squabbling comes down to: using the best data you can to assess a range of difficult questions.

The final enrollment number won't be 7.1 million; it will be the 80 to 85 percent of those people who pay their premiums. But that doesn't make 7.1 million a red herring — 80 percent of 7 million is a lot more than 80 percent of 5 million.

The number of uninsured people getting coverage is critical to evaluating the law's progress toward its broadest, most fundamental goals. It does not have much bearing on whether premiums go up next year, which is also an important question, because if premiums go up, enrollment might be lower. And enrollment matters.

It all matters.