Yesterday afternoon, the RAND Corporation published the first study following Obamacare's second open enrollment period to examine recent changes in U.S. health coverage. Like RAND's similar study from last year, it's a bit of puzzle, but an interesting and perhaps revealing one: It tells us quite clearly what's been apparent for quite a while now, which is that millions of people have gained health insurance following Obamacare's coverage expansion. But it also suggests the complexity and difficulty of determining exactly how those coverage gains have been achieved, and how much of the gain is directly tied to Obamacare.
The headline figure is that, on net, 16.9 million people have gained insurance between September 2013 and February 2015—with 22.8 million newly insured and 5.9 million having lost coverage during that time frame. But the vast majority of newly covered, according to the study, gained insurance through employer-sponsored plans rather than through the exchanges or Medicaid, Obamacare's primary coverage vehicles.
Changes in employer coverage practices as a result of the health law are probably part of the story, but job gains coming out of the recession are almost certainly part of it too. In other words, even with RAND's coverage breakdown, it's hard to pin down how much was a direct result of Obamacare, and how much was about the relative revival of the economy.
The study also suggests that exchanges may be mostly serving people who were previously covered. Of the 16.9 million people the study says gained coverage, on net, RAND's report finds that 4.1 million got coverage through the exchanges. That's only a fraction of the 11.2 million people the study estimates are covered through the exchanges; the other 7.1 million, the study says are people "who transitioned to marketplace plans from another source of coverage." Another study, however, found that more than half of exchange enrollees are newly insured.
RAND's study is useful and interesting, especially given its detailed breakdown of coverage types, but it also has a number of limitations: In particular, the study relied on a survey, which means that people may have incorrectly identified their insurance, and a fairly small sample size—just 1,589 "observations"—with a low response rate: just 9 percent. So while it provides a potential sketch as to what's happening, it's not the world's most precise measure.