KISS principle

KISS is an acronym for "Keep it simple, stupid" as a design principle noted by the U.S. Navy in 1960. The KISS principle states that most systems work best if they are kept simple rather than made complicated; therefore simplicity should be a key goal in design and unnecessary complexity should be avoided. The phrase has been associated with aircraft engineer Kelly Johnson (1910–1990). The term "KISS principle" was in popular use by 1970. Variations on the phrase include "Keep it Simple, Silly", "keep it short and simple", "keep it simple and straightforward" and "keep it small and simple".

Origin

The acronym was reportedly coined by Kelly Johnson, lead engineer at the Lockheed Skunk Works (creators of the Lockheed U-2 and SR-71 Blackbird spy planes, among many others).

While popular usage has transcribed it for decades as "Keep it simple, stupid", Johnson transcribed it as "Keep it simple stupid" (no comma), and this reading is still used by many authors. There was no implicit meaning that an engineer was stupid; just the opposite.