In an analysis that does not account for any health-care reform bill, the Department of Health and Human Services projected that health care expenditures would double from the 2009 level of $2.2 trillion (16.2% of 2009 GDP) to $4.4 trillion in 2018 (20.3% of projected 2018 GDP). This provides us a baseline from which to predict the cost-control effectiveness of health care reform.

I'm somewhat bullish on the potential of the pilot programs and the excise tax to lower med costs for a given level of health outcomes, although I'm not supremely confident in that. I also think there is a long tail of events or technologies that could unexpectedly increase med expenses (that would do so with or without health-care reform). Furthermore, the current bill will expand coverage for a substantial number of people, as a result of which total expenditures will definitely rise. All things together, here are my (very rough) intuitions:

• I'd give 1:1 odds that health-care expenditure is less than or equal to $5 trillion in 2018.
• I'd give 5:1 odds that it's less than or equal to $4 trillion in 2018.
• I'd give 5:1 odds that it's greater than $6 trillion in 2018.
• Conditioned on current health-care reform failing (i.e. no pilot programs or excise tax), I'd only give 2:1 odds that health-care expenditure is less than or equal to $4.4 trillion in 2018. (Long tails and overly rosy estimates.)

EDIT: I had this up for a few minutes with different numbers, before I remembered that the individual mandate and subsidies would raise med expenses significantly.