Sturgeon's law

Sturgeon's law: "Ninety percent of everything is crud." Derived from a quote by science fiction author Theodore Sturgeon, who once said, "Sure, ninety percent of science fiction is crud. That's because ninety percent of everything is crud." Oddly, when Sturgeon's law is cited, the final word is almost invariably changed to "crap".

(If memory serves me correctly, Harlan Ellison wrote in Again, Dangerous Visions that Sturgeon's original quote contained the word "crap:" a reporter asked him, "Mr. Sturgeon, isn't it true that 90 per cent of science fiction is crap?" "Sure, 90 per cent of science fiction is crap. But then, 90 per cent of everything is crap." (Perhaps someone who owns the book could confirm this?) -- HarmonicSphere)

Sturgeon's law might be regarded as an instance of the Pareto principle.

See also: Murphy's law -- Finagle's law -- Hanlon's razor -- Law (principle)