Usability

Usability refers to how well a product, service, or system meets the needs of a user in terms of ease, efficiency, and effectiveness. Meeting these qualities makes something more valuable to the user. It also makes it more likely to be successful and to be viewed favorably by consumers. Usability is related to how well something functions; however, usability and functionality are different qualities.

Background

The word usable comes from an old French word meaning “available.” Although the word came into use in the fourteenth century, it did not gain widespread usage until the middle of the nineteenth century. The idea of studying usability has its origins about 150 years ago.

In the early twentieth century, some researchers began looking into ways to improve the efficiency of various products and services. These researchers included industrial engineers Frank Gilbreth and his wife, Lillian Moller Gilbreth. The couple, who specialized in time and motion efficiency, had twelve children whom they raised according to their theories on time management and organization; they were the inspiration for the book and movies Cheaper by the Dozen.

By 1936, companies could see the advantages of promoting the usability of their products. Over the next several decades, there was an increased focus on improving usability. By the 1970s, scientists were making usability a formal topic of their research. During the last few years of the 1980s, experts began making usability their career specialty. In 1998, the concept had reached such universal acceptance that the International Organization for Standardization (ISO), a nongovernmental organization dedicated to creating standards to facilitate global interactions, adopted ISO 9241-11, a standard addressing the definition and basic requirements for usability.

Overview

The usability of a product, service, or system is an important consideration for anyone or any company designing something that will be used by others. While it is often thought of in terms of “ease of use,” usability goes beyond how easily something can be used. Something can be easy to use but not necessarily fulfill the needs of the user. For instance, a television might be very easy to operate, but if it cannot be turned off and on without a remote, it will not meet the user’s needs if the remote batteries are drained or the remote is missing. In other words, it is functional but not usable.

Experts list five characteristics that something must provide to its users for it to be considered usable. It should be effective, meeting the purpose for which the user needs it. It should be efficient, meeting that purpose with the least effort and time. It should be engaging, having appeal to the user while it is being used; for instance, a website should have interesting graphics appropriate to the site’s topic. It should be error-tolerant; this means both taking steps to help prevent user error—clearly labeled buttons, for instance—and making recovery from mistakes easy, such as giving the user a way to back out if an incorrect choice is made. It should be easy to learn; for example, if the settings menu on a television requires the use of the channel up and down buttons on one screen to set sound options, it should not require the use of the volume up and down buttons to set color options. These five attributes—effective, efficient, engaging, error-tolerant, and easy to learn—are called the five E’s of usability.

Understanding the potential user is the first step in ensuring usability. Designers will determine who the target audience for their product or service will be and what they will  expect from the item. It is also important to anticipate mistakes, unusual expectations, or unorthodox attempts the user might make. For instance, what happens if someone using an automated phone answering program to pay a utility bill wants to pay an amount larger than the amount due on the bill? A usable system should include an option that allows the input of the dollar amount, or if the company requires the customer to make these arrangements directly with a representative, the system should provide a means for the customer to speak to a representative. A system demonstrating usability would not permit the customer to make a payment that is not allowed, or would simply cut the customer off because of the unusual action.

As development is under way on a product, service, or system, it is necessary to assess usability at various stages in the process. This can be done using prototypes, simulations, or other means of having users interact with the item to determine how well it is meeting the users’ needs and expectations. It can also be accomplished through feedback, such as a “How did we do?” survey that pops up after someone uses a website. Designers should conduct regular evaluations as well, using a method appropriate for the item. For example, a mailed survey might be the best way to determine what people think of a new car design, while statistics about merchandise returns might be a good way to judge the usability of a new electronic device.

Usability has been deemed such a universally important concept that the ISO, an independent agency made up of 177 national standards bodies that establish standards and guidelines within a number of countries, has established guidelines and an official definition for usability. The ISO guidelines help with international trade by standardizing definitions and parameters for products, systems, and services that are recognized by all participating organizations. The ISO guidelines for usability are included in ISO 9241-11. First discussed in 1990, the guidelines were formally adopted in 1998. ISO’s 177 national standards bodies recommend these guidelines to the companies that look to them for standards, certification, and other services when engaging in global trade.

Bibliography

“About ISO.” International Organization for Standards, www.iso.org/about-us.html. Accessed 3 June 2026.

“Introduction to User-Centered Design.” Usability First, www.usabilityfirst.com/about-usability/introduction-to-user-centered-design. Accessed 3 June 2026.

Lewis, James R., and Jeff Sauro. “Usability and User Experience: Design and Evaluation.” Handbook of Human Factors and Ergonomics, 5th ed., Wiley, 2021, pp. 972–1015, doi:10.1002/9781119636113.ch38. Accessed 3 June 2026.

Ntoa, Stavroula. “Usability and User Experience Evaluation in Intelligent Environments: A Review and Reappraisal.” International Journal of Human-Computer Interaction, vol. 41, 2025, pp. 2829–58, doi:10.1080/10447318.2024.2394724. Accessed 3 June 2026.

Sauro, Jeff. “A Brief History of Usability.” Measuring U, 11 Feb. 2013, measuringu.com/usability-history/. Accessed 3 June 2026.

“Usability Evaluation Basics.” Usability.gov, www.usability.gov/what-and-why/usability-evaluation.html. Accessed 3 June 2026.

“What Does Usability Mean: Looking Beyond ‘Ease of Use.” WQusability, www.wqusability.com/articles/more-than-ease-of-use.html. Accessed 3 June 2026.