<P> Complex computer systems find their way into everyday life, and at the same time the market is saturated with competing brands . This has made usability more popular and widely recognized in recent years, as companies see the benefits of researching and developing their products with user - oriented methods instead of technology - oriented methods . By understanding and researching the interaction between product and user, the usability expert can also provide insight that is unattainable by traditional company - oriented market research . For example, after observing and interviewing users, the usability expert may identify needed functionality or design flaws that were not anticipated . A method called contextual inquiry does this in the naturally occurring context of the users own environment . In the user - centered design paradigm, the product is designed with its intended users in mind at all times . In the user - driven or participatory design paradigm, some of the users become actual or de facto members of the design team . </P> <P> The term user friendly is often used as a synonym for usable, though it may also refer to accessibility . Usability describes the quality of user experience across websites, software, products, and environments . There is no consensus about the relation of the terms ergonomics (or human factors) and usability . Some think of usability as the software specialization of the larger topic of ergonomics . Others view these topics as tangential, with ergonomics focusing on physiological matters (e.g., turning a door handle) and usability focusing on psychological matters (e.g., recognizing that a door can be opened by turning its handle). Usability is also important in website development (web usability). According to Jakob Nielsen, "Studies of user behavior on the Web find a low tolerance for difficult designs or slow sites . People don't want to wait . And they don't want to learn how to use a home page . There's no such thing as a training class or a manual for a Web site . People have to be able to grasp the functioning of the site immediately after scanning the home page--for a few seconds at most ." Otherwise, most casual users simply leave the site and browse or shop elsewhere . </P> <P> ISO defines usability as "The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use ." The word "usability" also refers to methods for improving ease - of - use during the design process . Usability consultant Jakob Nielsen and computer science professor Ben Shneiderman have written (separately) about a framework of system acceptability, where usability is a part of "usefulness" and is composed of: </P> <Ul> <Li> Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design? </Li> <Li> Efficiency: Once users have learned the design, how quickly can they perform tasks? </Li> <Li> Memorability: When users return to the design after a period of not using it, how easily can they re-establish proficiency? </Li> <Li> Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors? </Li> <Li> Satisfaction: How pleasant is it to use the design? </Li> </Ul>

What term is used to describe something that is useful and provide satisfaction