Med Mal Price Gouging?

I have an op-ed in today's Wall Street Journal on medical malpractice insurance premiums.  Here's a sample:

On its face, price gouging is a peculiar explanation for recent increases in insurance premiums. Is greed new to the world? Were insurance companies followers of Mother Teresa just a few years ago? If greed and gouging are the explanations for rising premiums, why did the St. Paul group -- one of the nation's largest suppliers of medical malpractice insurance -- pull out of the market in 2001? Were the profits from all that gouging just too much for St. Paul's guilty conscience? And consider that almost half of doctors are insured through mutual, i.e., doctor-owned, insurance companies. Are the doctors gouging themselves?

The gouging explanation fails more than the credulity test. Price gouging can work only if firms have monopoly power -- so if gouging is the explanation for higher premiums, we would expect to see higher premiums in states with less competition. My student, Amanda Agan, and I tested this hypothesis in a study released two days ago by the Manhattan Institute. Contrary to the gouging hypothesis, we found that a 10% increase in industry concentration reduces premiums by $2,200. The result makes sense if we remember that, to increase market share, firms don't raise prices but rather lower them. Wal-Mart has grown into the nation's dominant retailer by lowering prices, not raising them.