BackscatterTransportation, Aerospace & Aeronautics

KISS? “Yes.” TMO? “No.”

By Donald Christiansen

The design motto “Keep It Simple, Stupid” (KISS) was employed by the U. S. Navy in 1960 and popularized by Kelly Johnson, the lead engineer at the Lockheed Skunk Works. Johnson’s support of the KISS principle was based on the notion that Lockheed’s military systems (e.g., the SR-71 spy plane) must be repairable under combat conditions using unsophisticated tools.

Simplicity was thus sought as the key to system design. Yet it was not always adhered to as more complex systems arose in both civilian as well as military applications.

While the initial application of KISS principles focused on simplicity in design and maintenance of a system, not as much attention was given to simplicity of system operation.

The result was a major deterrent to KISS, namely TMO (Too Many Options), both in the added (often secondary) functions a system could provide as well as the variety of ways a particular function could be operated.

Too Many Options

Computer control of a majority of today’s systems has also diminished the user’s comprehension of how a system is constructed or how it can be repaired. It also enables the designer to add (and promote) options that may seldom be used by its owner. A system designed for use in a factory may be spared these unneeded options. Consumers, however, may be seduced by previously unavailable options.

In his recent article “10 ways that cars are becoming too complicated (and annoying),” Jack Sackman notes that high-end onboard navigation and infotainment systems have become the ultimate backseat driver. Also, he notes, in an effort to turn our vehicles into traveling living rooms we are offered so many distracting entertainment options that it affects our driving skills and attention.

Sackman, along with many others, asserts that cameras in cars are not necessarily a safety factor. He notes that blind spot alerts, lane departure warnings, and pedestrian and cyclist alerts are hypervigilant and can be distracting to our conventional driving practices.

Today’s dashboard indicators may cover fifteen or more malfunctions plus ten or more conditions requiring the driver to perform some action. These indicators differ in number and location on the instrument panel from one auto maker to another, and even among different models of the same make.

Planned Obsolescence

No surprise, the consumer’s wish to own products that are neither dated nor seemingly on the edge of obsolescence has resulted in the adoption of “planned obsolescence” by manufacturers of consumer products. This often results in the addition of “bells and whistles” that entice buyers but go largely unused. This concept, sometimes referred to as “dynamic obsolescence,” originated as far back as the early 1930s. The automotive market had not been growing as rapidly as anticipated, but when annual market-year changes were introduced, sales boomed.

During his long career with General Motors, Harley Earl, its famous design executive, was noted for many innovations, including the wrap-around windshield, bullet-shaped bumper guards, tailfins, integrated body design (’53 Corvette), and the rear-view TV camera (’56 Buick). In the earlier years, the added automotive features were principally in style as opposed to operation.

Some skeptics, unconvinced of the need to add new options to reliable existing products, favored the label “psychological obsolescence.” Whatever its designation, planned obsolescence is here to stay. Today, the computer has changed the nature of many added product features so that new options are operational in nature rather than based on non-functional design elements.

Overriding KISS

While seeking ultrasimplicity of design is a primary objective of KISS, there are design situations where complexity must be accepted. In high-reliability systems, for example, duplication of components or subsystems (redundancy) is necessary. And complexity may be increased when a user seeks a needed enhancement in the operation of a device or system. But be careful! Watch out for those unnecessary options.



  • R. Rich, Clarence Leonard (Kelly) Johnson 1910-1990 A Biographical Memoir, National Academics Press, 1995, p. 231.
  • Periwal, O., The KISS Principles for ORNL Products, retrieved July 13, 2019
  • Sackman, J., 10 ways that cars are becoming too complicated (and annoying)  retrieved July 13, 2019
  • Christiansen, D., “Designing Junk,” The Best of Backscatter, 1, p. 33, IEEE-USA, 2008.
  • Baghel, A. S., Software Design Principles: DRY, KISS, YAGNI   retrieved July 13, 2019
  • Schwartz, B., The Paradox of Choice—Why More Is Less, Harper Perennial, 2004.

Donald Christiansen

Donald Christiansen is the former editor and publisher of IEEE Spectrum and an independent publishing consultant. He is a Fellow of the IEEE. His Backscatter columns can be found here.

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