The six million number is an estimate made by the Congressional Budget Office (CBO) for year one enrollment in the new insurance marketplaces. They downgraded their estimate from seven million after the website woes slowed early enrollment. CBO estimates are made to gauge impact on the federal budget. Their purpose is not to judge the success or failure of the program. While it is true that the greater the number of enrollees the higher the likelihood of a balanced risk pool, six million is not a magic number. […]The number isn't unimportant, by any means, but it has probably more political significance at this point—since there has been enough enrollments nationally to sustain the program—than policy significance. The CBO said six million enrollments would be the target for the fiscal stability of the program, so it's become the goal supporters of the law are pushing for and Republicans are rooting against.
Also, there is no national risk pool, so the percentage of the six million who are young or anything else doesn’t matter all that much. Under the law risk is pooled at the state level, so what matters is the risk profile in each state and there will be variation across the country with more and less balanced risk pools in different states. Premiums themselves are set on a smaller geographic basis, so they will vary even more depending on market competition and other factors in local markets.
But it's at the local and state level where relative success of the program will be determined, and that's not going to shake out for a while. We can make some informed guesses best on health status data about where there will be problems with risk-pools, where the newly insured population is going to be less healthy and more expensive, but at this point we don't really know for sure that, even in those areas, premiums will be driven higher. What we do know, though, is that if they do go up, Republicans will scream about it.
With any hope, Democrats will respond with the policy proposal that could still create the competition needed to help keep premiums overall lower—Medicare expansion or some other public option.
Watching enrollments is still fun for us geeks, so keep up with them at Brainwrap's ACASignups.net.