Generally speaking, the most important evidence in medical malpractice cases are the medical records. Those records usually provide the most direct insight into the situation at hand.
Medical literature, including textbooks and peer-reviewed journal articles, provide important information on medical standards. Oftentimes, however, because each patient’s situation is different, the literature does not tell the whole story. Expert witness opinion and testimony can help fill the gaps, as well as testimony from medical providers who were on the scene, or testimony from other witnesses.