At the an interesting-looking, and relatively new polisci blog, Rule22 (yes, that Rule 22), Jordan Ragusa takes a crack at this and supplies more detail here about a forthcoming article on repeals of major legislation.
Ragusa notes, of course, that no one thinks health care reform will be repealed in its entirety and that “repeal” is a catch-all for various proposed modifications to the ACA. In the paper, he defines repeal as repeal of at least one major provision. Ragusa then examines a large dataset of “landmark laws” from 1951-2006 and uses a hazard model to estimate the likelihood of “death” (i.e., repeal).
He finds that for the first 10 years after enactment, policies become increasingly likely to be repealed, maxing out at 13% . After the 10-year mark, the probability of repeal declines consistently. After 40 years, the chance of repeal is maybe 3%.
Here’s a graph that shows how the probability of repeal for each 2-year period (i.e., Congress) after passage.
During “disequilibrium” (t<10 years) policies are increasingly likely to be repealed as time passes. At the second stage, delineated by the maximum of the hazard function, the likelihood of any repeal is about 13%...I refer to this period as a "policy reversal window of opportunity." After this point the instantaneous likelihood of repeal decreases monotonically over the life of a policy. In this final stage, “equilibrium” (t>10 years), each year that passes renders existing policies less likely to be repealed.
Ragusa then uses his statistical model to predict the chance of repealing health care (with caveats, of course; see his post). Here is the upshot: depending on the future partisan control of the presidency and Congress, the probability of repeal of at least one major provision of the health care reform bill ranges between 52% and 69%.
…the newly enacted law will be most “at risk” not in the next Congress, but a decade from now. So sit tight.
[And] there are some serious constraints the Republican Party will have to overcome to make major changes to the original law. True, some repealing activity is likely to succeed. But this is more a function of the law’s size than anything else. Still, if Democrats can maintain the Senate in 2010, and hold the White House in 2012, their prospects of defending the law from “repeal” is significantly greater.