The adverse selection story is a wonderful example of McCloskey’s argument that great rhetoric persuades even when it shouldn’t. The market for lemons is simple enough for your friends to understand but profound enough for them to be impressed at your learning, so it’s a hard story not to tell!
One reason adverse selection may not be that important in practice is because buyers and sellers use testing and certification to remove the most important information asymmetries. You can buy a decent used car, for example just get it inspected or certified. Only if such adjustments are illegal, or in some other way not allowed, will adverse selection become important.
Second, the asymmetry may run in favor of the sellers. Do I really know more about my own life expectancy than an insurance firm that has access to sophisticated actuarial models? And, assuming that I do have extra information is it all that important? After all "the race is not to the
swift, nor the battle to the strong, neither yet bread to the wise… but
time and chance happen to them all." Or, more prosaically, the signal is near irrelevant when the noise to signal ratio is high.
Third, propitious selection can be more important than adverse selection. What sort of person buys a lot of life insurance? Is it people who expect to die soon? Or is it the sort of person who is so worried about not leaving their family in trouble that not only do they buy life insurance they also buckle their safety belt and eat healthy? The price of life insurance falls the more you buy so evidently insurance companies believe it is the latter.
Everyone talks about adverse selection in the market for health insurance but in fact non-group policies in these markets are not relatively expensive and not hard to get. The national average annual premium for reasonably generous coverage for a single person is just $2,268.
Sure, that’s a lot of money but the point is that it’s not a lot relative to what an employed person and their employer would pay for similar coverage in the group market. There is no evidence for an adverse-selection death spiral in the market for health insurance. That’s not surprising because non-group health insurance is medically underwitten (i.e. medical inspections just like car inspections). Most people are accepted a few are not. Only in states that require insurance companies to accept all or most buyers are rates high relative to the group market (rates in New Jersey, an outlier, are almost three times as high as the national average.)
There are problems in the health insurance market, including a lack of long term insurance, job lock and the inequity of affordability, but adverse selection is not one of them.
Addendum: Comments are open.