Despite medical advances and the application of scientific principles to modern medicine, there seems to be increasing controversy about the "right" diagnostic and treatment choices, even for very common medical issues – such as how best to treat high blood pressure and elevated cholesterol; whether to take vitamins, and who should be screened for cancer with mammograms and PSA. Doctors Jerome Groopman, chair of Harvard Medical School, and Pamela Hartzband, assistant professor at Harvard Medical School, discuss why experts disagree, why there isn't a clear "right" answer, and what patients need to know to make decisions in the face of conflicting information.