Jurors' decision-making processes are often influenced by extra-legal factors, including judgments of defendants and plaintiffs. Two studies comparing the decisions of university students with those of community jurors sought to determine if extra-legal factors such as individual differences (including identity as a student or juror participant), the reason for surgery (medically necessary vs. elective), the type of surgery (e.g., gastric bypass, nasal reconstruction) or weight of the patient influenced jurors' decisions and perceptions in medical malpractice suits, such that participants would hold negative perceptions of overweight patients or patients who undergo elective surgeries. Results indicate that students and jurors differ in perceptions of the patient's injury and perceptions of risk, which explains some of the variance in liability verdicts. Students were more likely to find doctors liable, but also were more likely to assign responsibility to patients than were jurors. Patients who had undergone elective surgery were seen as more responsible for their situation – and their doctors were assigned less responsibility – than those who had undergone a medically necessary surgery. Tests of weight bias showed that jurors found overweight patients less responsible for their situation than patients of normal weight, but students showed the opposite pattern. Theoretical explanations are explored and implications discussed. Copyright © 2011 John Wiley & Sons, Ltd.