Let’s say you are a health policy expert and you are sitting in your office and you receive a phone call from a news reporter. The reporter asks you to comment for a story she is writing. She has learned from the chief of neurosurgery at Cooper University Hospital that the mortality rate for neurosurgery performed with their robotic system is 8%. This chief also states that the mortality rate for patients with neurosurgery conducted at University of Pennsylvania (which doesn’t have the robotic system) is 18%. The Cooper Hospital public relations department plan s a media campaign to promote the superior outcomes for neurosurgery with the robotic system and the reporter plans to write that patients who have neurosurgery without the robotic system are twice as likely to die as those who have robotic-assisted surgery. You explain that the direct comparison of the two mortality rates may not be adequate to determine success. You mention the comparison could be confounded.

Question

a. Describe confounding as you might to a newspaper reporter.

b. Please list 3 possible (and reasonable) confounders and describe how they might influence the results in this example (meaning how would they affect the measure of risk or association)