There is ongoing policy debate about the potential for malpractice liability reform to reduce the use of defensive medicine and slow the growth of health care spending. The effectiveness of such policy levers hinges on the degree to which physicians respond to liability pressures by prescribing medically unnecessary care. Many estimates of this relationship are based on physician reports. We present new survey evidence on physician assessment of their own use of medically unnecessary care in response to medical liability and other pressures, including a randomized evaluation of the sensitivity of those responses to survey framing. We find that while use of such care is potentially quite prevalent, responses vary substantially based on survey framing, with the way the question is phrased driving differences in responses that are often as great as those driven by physician specialty or whether the physician has personally been named in a lawsuit. These results suggest that self-reported use of medically unnecessary care ought to be used with caution in the formulation of malpractice liability system reform.