Gawande catalogues the many noteworthy superstitions of performers, athletes, and coaches to provide contrast with doctors, who, in Gawande’s experience, rarely exhibit superstitious behavior. Doctors are scientists who are “usually uncomfortable, if not downright contemptuous, of the mystical” (110). He’s surprised, then, when his colleagues seem to be avoiding signing up for an emergency shift on Friday the 13th. A full moon and a lunar eclipse also happen to fall on that Friday. Gawande, eschewing superstition, signs up for the shift. One resident tells him to “rest up.”

Curious, Gawande investigates studies about Friday the 13th and full moons. He believes Friday the 13th to be an example of the “Texas sharpshooter fallacy” (111), which explains how humans identify patterns that don’t exist around random events. Of the two superstitions, Gawande is more inclined to believe that humans might be affected by lunar activity, since evidence shows human are affected by the seasons and circadian rhythms. He finds sparse evidence, but a couple of studies seem to suggest people are safer during full moons than new moons.

Despite little data and much skepticism, Gawande shows up for his shift on Friday the 13th and experiences an onslaught of patients and an unprecedented amount of work.