According to a Harvard study, about $45 billion is spent each year on defensive medicine. That amount comprises only about 2.4% of total medical expenditures in the U.S.
If you enacted tort reform, in theory you may be able to cut 25% of those defensive medicine practices and then maybe only $30 billion is spent each year on defensive medicine. That is still less than 2% of all medical expenditures in the U.S. per year.
In Texas, they enacted caps on med mal lawsuits, and health care costs are still rising at a greater rate.
Defensive medicine is negligible when looking at total health care costs.
http://www.forbes.com/sites/rickungar/2010/09/07/the-true-cost-of-medical-malpractice-it-may-surprise-you/#1319ac349ccd