KISS principle

"K-I-S-S" redirects here. For other uses, see Kiss (disambiguation).

KISS is an acronym for the design principle "Keep it simple, Stupid!",. Other variations include "keep it short and simple" or "keep it simple and straightforward". The KISS principle states that simplicity should be a key goal in design, and that unnecessary complexity should be avoided.

Some propose that it should follow its own advice by dropping the redundant letter and be just KIS, "keep it simple". Others believe that this final point is, in fact, essential.

Related concepts

The acronym was first 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 translates is as 'Keep it simple, stupid', Johnson translated it as 'Keep it simple stupid', and this reading is still used by many authors. There was no implicit meaning that an engineer was stupid; just the opposite.

The principle is best exemplified by the story of Johnson handing a team of design engineers a handful of tools, with the challenge that the jet aircraft they were designing must be repairable by an average mechanic in the field under combat conditions with only these tools. Hence, the 'stupid' refers to the relationship between the way things break and the sophistication available to fix them.

The acronym is used by many in the United States Air Force

The principle most likely finds its origins in similar concepts, such as Occam's razor, and Albert Einstein's maxim that "everything should be made as simple as possible, but no simpler". Leonardo Da Vinci's "Simplicity is the ultimate sophistication", or Antoine de Saint Exupéry's "It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away".

Colin Chapman, the founder of Lotus Cars, urged his designers to "Simplify, and add lightness".

Rube Goldberg's machines, intentionally overly-complex solutions to simple tasks or problems, are humorous examples of "non-KISS" solutions.

Instruction creep and function creep, two instances of creeping featuritis, are examples of failure to follow the KISS principle in software development. Similarly, scope creep exemplifies failure to follow KISS in project management.

In film animation

Master animator Richard Williams explains the KISS Principle in his book The Animator's Survival Kit, and Disney's Nine Old Men write about it in Disney Animation: The Illusion of Life, which is considered "the animation bible" by CG, traditional and stop motion animators. Inexperienced animators may "overanimate", or make their character move too much and do too much, such as carrying every accent over into body language, facial expression, and lipsync. Williams urges animators to "KISS".

See also

• Don't repeat yourself (DRY)
• Minimalism
• Pareto principle 80:20 rule
• Sysico principle
• W. Heath Robinson
• Worse is better
• You ain't gonna need it (YAGNI)
• Kiss Principle

References

• http://quotiki.com/quote.aspx?id=7923 – This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.