From today’s New York Times:

But for all the worry over higher medical expenses, legal costs do not seem to be at the root of the recent increase in malpractice insurance premiums. Government and industry data show only a modest rise in malpractice claims over the last decade. And last year, the trend in payments for malpractice claims against doctors and other medical professionals turned sharply downward, falling 8.9 percent, to a nationwide total of $4.6 billion, according to data compiled by the Health and Human Services Department. […]

Lawsuits against doctors are just one of several factors that have driven up the cost of malpractice insurance, specialists say. Lately, the more important factors appear to be the declining investment earnings of insurance companies and the changing nature of competition in the industry. […]

Data compiled by both the federal government and by insurance organizations show costs for the insurance companies climbing steadily over the last decade at an average annual rate of about 3 percent, after adjusting for inflation. Over most of that period, premiums for doctors rose modestly and sometimes even dropped as the insurance companies battled for market share in a scramble to collect more money to invest in strong bond and stock markets. But when the markets turned sour and the reserves of insurers shriveled, companies began to double and triple the costs for doctors. […]

And some researchers are skeptical that caps ultimately reduce costs for doctors. Mr. Weiss of Weiss Ratings and researchers at Dartmouth College, who separately studied data on premiums and payouts for medical mistakes in the 1990’s and early 2000’s, said they were unable to find a meaningful link between claims payments by insurers and the prices they charged doctors.

“We didn’t see it,” said Amitabh Chandra, an assistant professor of economics at Dartmouth. “Surprisingly, there appears to be a fairly weak relationship.”

Go read the whole thing.