Jury service is one of the few obligations of citizenship that arrives without warning and cannot easily be declined. It is also, by design, work for people with no expertise in the matter at hand. That combination strikes many people as odd: why hand a difficult decision to twelve strangers chosen at random? The answer usually given is that the alternative is worse. A professional decider, however skilled, becomes predictable, and a system whose outcomes can be predicted can be worked around. Randomness is not a flaw in the design. It is a large part of what the design is for.