Executive Summary Everyone takes and manages risks, balancing potential rewards against uncertain losses.
Experts provide advice about managing risk, but with limited success.
Part of their difficulty stems from an incomplete appreciation of the different kinds of risk and part from their inadequate consideration of the different mindsets with which people respond to risks. Directly perceptible risks are managed instinctively and intuitively. Professional attempts to manage them are thwarted by people who insist on being their own risk managers. Risks perceptible with the help of science include infectious diseases. Quantitative estimates of such risks are frustrated by the reflexivity of risk.