The movie, Waiting for Superman, provides the following factoid:
About one of 57 medical doctors and one of 97 lawyers loses his or her license annually for malpractice. In contrast, only one in 2,500 unionized, public school teachers with tenure gets fired each year.
Okay, I can’t find original source and the quote, on its face, is wrong. Doctors and lawyers are losing their licences for bad and inappropriate behavior. There are not a lot of good guy doctors and lawyers losing their licences for not being good at their jobs, i.e. malpractice. Maybe there should be. But there is not.
I have always thought that the medical profession does a poor job of regulating itself. But this data does suggest otherwise (assuming it is correct and all other things being close to equal).