The KISS principle is an acronym of “keep it simple, stupid”, a phrase thought to have been coined by Lockheed engineer Kelly Johnson. The KISS principle argues most systems work best when they are simple and not complicated.
Understanding the KISS principle
Johnson explained the reasoning behind his phrase with a simple story. While briefing aircraft designers at Lockheed, he told them that whatever they made had to be something a basic mechanic could repair in the field with limited tools. If Lockheed’s designs were not easy to understand, they would quickly become obsolete in the combat conditions for which they were made.
Today, many practitioners of the idea believe it may have been the first usability principle in product design. For a product to gain maximum market share, the vast majority of the target audience must know how to use it. What’s more, simple products tend to work better because they have fewer moving parts, so to speak. These concepts are as true for software engineering and mobile applications as they are for Lockheed fighter planes.
The KISS principle and consumers
When a consumer is weighing up a purchasing decision, they do not care how long the product was in development or how intelligently it was manufactured. Instead, their primary concern is whether they can use the product to satisfy certain outcomes.
Products with simple explanations also tend to sell better than those with more complex explanations. For product teams, simplicity is found by working backward from what the customer needs and omitting any feature that does not serve this purpose. Superfluous product design may be related to convoluted or excessive features, policies, procedures, steps, or systems.
The same argument can also be made for eCommerce companies. Website navigation should be as simple as possible and every barrier to the customer making a purchase should be removed.
Lastly, the KISS principle is crucial in software design, where function and instruction creep can make programs unmanageable over time. It is also important in designing a minimum viable product and doing the least amount of work necessary to prove or disprove a hypothesis.
Many of these points may seem counterintuitive to some organizations – but they are well worth keeping in mind.
Variants of the KISS principle
Although the modern KISS principle was developed around 50 years ago, similar ideas were common centuries earlier.
For example:
- Leonardo da Vinci (1452-1519) once said that “Though human ingenuity may make various inventions which, by the help of various machines answering the same end, it will never devise any inventions more beautiful, nor more simple, nor more to the purpose than Nature does; because in her inventions nothing is wanting, and nothing is superfluous.”
- Occam’s Razor – a fourteenth-century theory stating that from a series of hypotheses, the simplest one is most likely to be correct unless proven otherwise.
- Albert Einstein (1879-1955) also said that “Everything should be made as simple as possible, but not simpler.” As a scientist, Einstein may have been paraphrasing Occam’s Razor.
- Bjarne Stroustrup (b. 1950) once said “Make simple tasks simple.” Stroustrup is a Danish computer scientist who developed the C++ programming language.
Key takeaways:
- The KISS principle argues most systems work best when they are simple and not complicated. The theory behind the principle has existed for centuries, but it was popularised by Lockheed engineer Kelly Johnson.
- The KISS principle has wide-ranging applications in software engineering, website design, product design, and customer experience. Ultimately, the end-user is only concerned with whether a product meets their needs or wants.
- Variations of the KISS principle have been mentioned by Leonardo da Vinci, Albert Einstein, and Danish computer scientist Bjarne Stroustrup.
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