What Is The KISS Principle? The KISS Principle In A Nutshell

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:

  1. 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.” 
  2. 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. 
  3. 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.
  4. 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.

Connected Business Concepts

First-Principles Thinking

First-principles thinking – sometimes called reasoning from first principles – is used to reverse-engineer complex problems and encourage creativity. It involves breaking down problems into basic elements and reassembling them from the ground up. Elon Musk is among the strongest proponents of this way of thinking.

Ladder Of Inference

The ladder of inference is a conscious or subconscious thinking process where an individual moves from a fact to a decision or action. The ladder of inference was created by academic Chris Argyris to illustrate how people form and then use mental models to make decisions.

Six Thinking Hats Model

The Six Thinking Hats model was created by psychologist Edward de Bono in 1986, who noted that personality type was a key driver of how people approached problem-solving. For example, optimists view situations differently from pessimists. Analytical individuals may generate ideas that a more emotional person would not, and vice versa.

Second-Order Thinking

Second-order thinking is a means of assessing the implications of our decisions by considering future consequences. Second-order thinking is a mental model that considers all future possibilities. It encourages individuals to think outside of the box so that they can prepare for every and eventuality. It also discourages the tendency for individuals to default to the most obvious choice.

Lateral Thinking

Lateral thinking is a business strategy that involves approaching a problem from a different direction. The strategy attempts to remove traditionally formulaic and routine approaches to problem-solving by advocating creative thinking, therefore finding unconventional ways to solve a known problem. This sort of non-linear approach to problem-solving, can at times, create a big impact.

Moonshot Thinking

Moonshot thinking is an approach to innovation, and it can be applied to business or any other discipline where you target at least 10X goals. That shifts the mindset, and it empowers a team of people to look for unconventional solutions, thus starting from first principles, by leveraging on fast-paced experimentation.

Tim Brown, Executive Chair of IDEO, defined design thinking as “a human-centered approach to innovation that draws from the designer’s toolkit to integrate the needs of people, the possibilities of technology, and the requirements for business success.” Therefore, desirability, feasibility, and viability are balanced to solve critical problems.


The concept of cognitive biases was introduced and popularized by the work of Amos Tversky and Daniel Kahneman since 1972. Biases are seen as systematic errors and flaws that make humans deviate from the standards of rationality, thus making us inept at making good decisions under uncertainty.

Bounded Rationality

Bounded rationality is a concept attributed to Herbert Simon, an economist and political scientist interested in decision-making and how we make decisions in the real world. In fact, he believed that rather than optimizing (which was the mainstream view in the past decades) humans follow what he called satisficing.

Dunning-Kruger Effect

The Dunning-Kruger effect describes a cognitive bias where people with low ability in a task overestimate their ability to perform that task well. Consumers or businesses that do not possess the requisite knowledge make bad decisions. What’s more, knowledge gaps prevent the person or business from seeing their mistakes.

Occam’s Razor

Occam’s Razor states that one should not increase (beyond reason) the number of entities required to explain anything. All things being equal, the simplest solution is often the best one. The principle is attributed to 14th-century English theologian William of Ockham.

Mandela Effect

The Mandela effect is a phenomenon where a large group of people remembers an event differently from how it occurred. The Mandela effect was first described in relation to Fiona Broome, who believed that former South African President Nelson Mandela died in prison during the 1980s. While Mandela was released from prison in 1990 and died 23 years later, Broome remembered news coverage of his death in prison and even a speech from his widow. Of course, neither event occurred in reality. But Broome was later to discover that she was not the only one with the same recollection of events.

Crowding-Out Effect

The crowding-out effect occurs when public sector spending reduces spending in the private sector.

Bandwagon Effect

The bandwagon effect tells us that the more a belief or idea has been adopted by more people within a group, the more the individual adoption of that idea might increase within the same group. This is the psychological effect that leads to herd mentality. What in marketing can be associated with social proof.

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