Source, in full
Venture Science Fiction (March 1958) The original expression of this has often been declared to have been "Sure, ninety percent of science fiction is crud. That's because ninety percent of everything is crud." According to Philip Klass Sturgeon made the remark during a talk at New York University around 1951. It has also commonly appeared in variant forms such as "Ninety percent of everything is crap" and is often referred to as "Sturgeon's Law" — though he himself gave that title to another phrase