A slim majority of Obamacare's private insurance enrollees were uninsured when they signed up for coverage, a new survey from the Kaiser Family Foundation finds.
Obamacare opponents have regularly argued that most enrollees already had coverage, meaning that health reform wasn't driving down the uninsured rate.
The new Kaiser survey, which uses a randomly-selected panel of 742 people who bought private coverage through the new exchanges, finds that 57 percent of those who signed up for private coverage didn't have an insurance plan when they enrolled.
The Kaiser survey suggests that most people who bought on the marketplace weren't trying to replace a plan they already had. They were people who lacked insurance coverage, and were using the new health care law to gain access to a plan they didn't have before.
Every study asks its questions differently
Here's the thing that's so frustrating in trying to sort out this question about who was uninsured: the variation between different groups' estimates is just massive.
When you dig into the methodology, as health wonks are wont to do, you start to notice that the surveys happened at different times, with different people who were asked different questions. A quick run-down:
The McKinsey report, conducted during the second week of April, used a non-random sample of people who buy insurance on the individual market and elected to be part of an online survey. It found that a much-smaller 24 percent of exchange enrollees were uninsuredwhen they signed up.
To measure who had coverage, McKinsey asked people to identify the insurance they had "most of the year" in 2013. This would mean that an Obamacare enrollee who, for example, lost their employer coverage in August and bought an exchange plan in December would be counted as someone who did have previous coverage.
The RAND estimate relies on the research firm's ongoing American Life Panel, a set group of people who it regularly asks different research questions. Since November, RAND has asked this group about its health insurance status. It found that, when it reached out to them mostly in early March, that 36 percent of those who had exchange coverage were, in earlier surveys, uninsured.
RAND collected most of its enrollment data before the big sign-up surge in late March and early April. Researchers note in their report "some may have made new insurance choices since participating in our survey."
Health and Human Services has estimated 87 percent of certain Obamacare enrollees lacked coverage when they signed up. This figure comes from a question on Healthcare.gov, that the federal government required any shopper applying for subsidies to answer. Since the vast majority of shoppers did apply for subsidy, 5.18 million people answered this question — and only 13 percent indicated they had insurance at the time they were filling out the application. This figure misses anyone who bought coverage on a state exchange, and those who did not apply for subsidies.
Last, there's the new Kaiser Family Foundation report. It uses a random sample of 742 people who bought a plan on an Obamacare exchange (either Healthcare.gov or one of the state-run marketplaces). It asked survey respondents this question: "Before you began coverage under your current health insurance plan, were you covered by a different plan you purchased yourself, were you covered by an employer, by COBRA, did you have Medicaid or other public coverage, or were you uninsured?"
Which number is right?
No survey has gone out and measured all 8 million Obamacare enrollees, asking each and everyone whether they had health insurance coverage when they bought a plan on the marketplace.
The new Kaiser Family Foundation survey is the most up-to-date, randomized study that specifically asks people to identify what coverage source they had prior to signing up on the exchange.
This separates it from RAND (whose survey data misses the end of open enrollment), McKinsey (which asks a slightly different question) and the Obama administration estimate (it leaves out anyone buying through a state exchange).
Will the Kaiser survey be the last word? Probably not: given all the variation in estimates, this is an area that political pundits will keep debating and health researchers will keep researching. Measuring health insurance status is tricky; depending on how pollsters phrase questions, it can change whether people say they have coverage. But the Kaiser numbers are, at this point, a pretty decent gauge of who exactly signed up for coverage, and what their situation was beforehand.