13 years, 3 months ago

Black Swans and Complex System Failure

Black Swan theory (Wikipedia) tells us among other things that people tend to underestimate the probability of extremely rare events.

A corollary of this theory that is of particular interest to architects and complex system engineers concerns the design of fail-safe mechanisms. Nuclear power and oil extraction are examples of environmentally critical operations; they are therefore subject to detailed risk assessment, and designed with multiple fail-safe mechanisms. And yet both the oil spillage last year in the Gulf of Mexico and the partial melt-down in Japanese nuclear reactors following the recent tsunami involved the simultaneous failure of multiple fail-safe mechanisms. Obviously that’s not supposed to happen.

Simultaneous failure of supposedly independent mechanisms is a Black Swan event.