Feb. 4 (Bloomberg) — You've probably already read that the Congressional Budget Office thinks the U.S. health-care overhaul will reduce employment by the equivalent of about 2 million jobs in 2017. Republicans are saying it will cost 2 million jobs; the White House, meanwhile, is framing this as a choice that people are now free to make. Here's what you need to know:

– The CBO is not an all-powerful seer that gazed into its crystal ball and foresaw an army of unemployed rising from the barren wastes of the Patient Protection and Affordable Care Act. It is full of very smart people who are phenomenally dedicated to their appointed tasks. But those people frequently work with very incomplete information, and this is one of those cases. We've never done this before, and 2 million may be an overestimate, it may be an underestimate or it may be just right. We may never even know which of those three was the case; any disemployment effect is going to be hard to pick out of the statistical noise.

– Most of the projected disemployment will be voluntary — people leaving the workforce because they no longer need to work to maintain their health insurance. Or second earners who look at the extra income they get from their jobs, look at the amount it will cost the family in child care, other expenses, and lost Obamacare subsidies, and decide they might as well stay home. The CBO is not saying that millions of people will be thrown out of work because of Obamacare; it's saying that millions of people will be leaving of their own accord.