i have done quite a bit of research on this in the past and there are some interesting facts that arise.
If you look at the lengths we go to now to minimise error in aviation, i.e Mandated CRM and Human Factors for starters, we are now in a position where we as a profession are pretty safe. In 2004, there were approximately 16 million air movements world wide. Approx 2500 people died in air incidents (many in light aircraft).
In the same year alone, it is estimated by the insurance companies that almost 750,000 people died as a result of medical negligence in the United States alone!! Yes you read the right number. The total figures are split into about 10 cause groups, of which Surgical error was one, which accounted for just over 30,000 deaths. It is estimated that the deaths run at a rate equivelent per capita of population, interestingly this turns out to be about in the right ball park as in the same year it is estimated that 70, 000 people died in the UK as a result of medical negligence of one form or another. Major contributing factors do seem to be the communication issues, fatigue, stress and lack of supervision (due to undermanning).
Back to the USA in the same year 530K people died as a result of cardiac disease, and 510K people died as a result of cancer. Therefore Human error killed more people than either Cancer or Cardiac disease. Think of the money we (quite rightly) put into research in both these disease types, and compare to how much we put into the prevention of deaths caused by Human Error in medicine!
Any Surgeons, Docs interested in a little (infact huge) project? Pm me.