Last spring I was very suspicious of the RAND study that claimed a good deal of the net gain in insured individuals was from people who picked up employer sponsored insurance (ESI). I thought it could have been a sampling problem as the subset was very small with a large margin of error in both percentage and absolute terms. Others thought there was a methodological flaw :
This poll is unusual in that it interviewed the same people twice, first in September and then again in March. This allows it to see how many of the sample actually change from one type of cover to another. But its weakness is that inevitably somewhere between 5 and 10% of the people you interviewed in the first round can’t be contacted again. Some may refuse to answer more questions, but more likely the phone number has been disconnected. RAND reports that 2641 people were interviewed in September but only 2,425 of these (91.8%) were interviewed in March. So RAND went ahead with those who answered both surveys, assuming that were similar to the whole population.
The RAND study’s headline results were similar to everyone else’s on changes/improvements to the uninsured rate from early last fall to after the end of the open enrollment period. It was just their subdivision of how people gained insurance was wrong. They were the only ones to attribute a large proportion of the coverage increases to ESI taking off, and thus a much smaller proportion of the gain to either Medicaid expansion, woodworkers or Exchange policies. It did not pass the immediate smell test.
However, there is a very interesting nugget from Walmart that supports the Rand theory:
The nation’s largest retailer said Thursday it now expects to spend about $500 million for U.S. health-care costs this year, up from a previous estimate of $330 million. A larger number of employees seeking coverage as well as other medical costs that are rising contributed the company’s higher expenses and its decision to trim its earnings forecast for the year.
Rand’s theory was that the threat of a mandate payment got a lot of people who were making the marginal decision to not get coverage at work to get coverage from work. Walmart seeing their health insurance costs increase by 50% in a year where health insurance inflation is between 6% to 9% strongly suggests most of that added cost is being driven by more people getting covered by Walmart.