Editing Usability (section)

==Definition==
[[International Organization for Standardization|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 (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:<ref>[http://www.useit.com/alertbox/20030825.html Usability 101: Introduction to Usability] {{webarchive|url=https://web.archive.org/web/20110408184029/http://www.useit.com/alertbox/20030825.html |date=2011-04-08 }}, Jakob Nielsen's Alertbox. Retrieved 2010-06-01</ref>
* [[Learnability]]: How easy is it for users to accomplish basic tasks the first time they encounter the design?
* Efficiency: Once users have learned the design, how quickly can they perform tasks?
* Memorability: When users return to the design after a period of not using it, how easily can they re-establish proficiency?
* Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
* Satisfaction: How pleasant is it to use the design?

Usability is often associated with the functionalities of the product (cf. [[International Organization for Standardization|ISO]] definition, below), in addition to being solely a characteristic of the user interface (cf. framework of system acceptability, also below, which separates ''usefulness'' into ''usability'' and ''utility''). For example, in the context of mainstream consumer products, an automobile lacking a reverse gear could be considered ''unusable'' according to the former view, and ''lacking in utility'' according to the latter view. When evaluating user interfaces for usability, the definition can be as simple as "the perception of a target user of the effectiveness (fit for purpose) and efficiency (work or time required to use) of the Interface"{{Citation needed|date=February 2013}}. Each component may be measured subjectively against criteria, e.g., Principles of User Interface Design, to provide a metric, often expressed as a percentage. It is important to distinguish between usability testing and usability engineering. [[Usability testing]] is the measurement of ease of use of a product or piece of software. In contrast, [[usability engineering]] (UE) is the research and design process that ensures a product with good usability. Usability is a [[non-functional requirement]]. As with other non-functional requirements, usability cannot be directly measured but must be quantified by means of indirect measures or attributes such as, for example, the number of reported problems with ease-of-use of a system.

===Intuitive interaction or intuitive use===
{{see also|Natural user interface}}
The term [[Intuition (knowledge)|intuitive]] is often listed as a desirable trait in usable interfaces, sometimes used as a synonym for [[learnability|learnable]]. In the past, [[Jef Raskin]] discouraged using this term in user interface design, claiming that easy to use interfaces are often easy because of the user's exposure to previous similar systems, thus the term 'familiar' should be preferred.<ref>[http://www.asktog.com/papers/raskinintuit.html Intuitive equals familiar] {{webarchive|url=https://web.archive.org/web/20091005202036/http://www.asktog.com/papers/raskinintuit.html |date=2009-10-05 }}, Communications of the ACM. 37:9, September 1994, pg. 17.</ref> As an example: Two vertical lines "||" on media player buttons do not intuitively mean "pause"&mdash;they do so by convention. This association between intuitive use and familiarity has since been empirically demonstrated in multiple studies by a range of researchers across the world, and intuitive interaction is accepted in the research community as being use of an interface based on past experience with similar interfaces or something else, often not fully conscious,<ref>{{Cite book |title=Intuitive interaction : research and application |date=2018 |editor=Alethea Blackler |publisher=CRC Press |isbn=978-1-315-16714-5 |location=Boca Raton, FL |oclc=1044734346}}</ref> and sometimes involving a feeling of "magic"<ref>{{Cite book |last1=Ullrich |first1=Daniel |last2=Diefenbach |first2=Sarah |title=Proceedings of the 6th Nordic Conference on Human-Computer Interaction: Extending Boundaries |chapter=From magical experience to effortlessness |date=2010-10-16 |chapter-url=https://doi.org/10.1145/1868914.1869033 |series=NordiCHI '10 |location=New York, NY, USA |publisher=Association for Computing Machinery |pages=801–804 |doi=10.1145/1868914.1869033 |isbn=978-1-60558-934-3|s2cid=5378990 }}</ref> since the course of the knowledge itself may not be consciously available to the user . Researchers have also investigated intuitive interaction for older people,<ref>{{Cite journal |last1=Lawry |first1=Simon |last2=Popovic |first2=Vesna |last3=Blackler |first3=Alethea |last4=Thompson |first4=Helen |date=January 2019 |title=Age, familiarity, and intuitive use: An empirical investigation |url=https://linkinghub.elsevier.com/retrieve/pii/S0003687018302898 |journal=Applied Ergonomics |language=en |volume=74 |pages=74–84 |doi=10.1016/j.apergo.2018.08.016|pmid=30487112 |s2cid=54105210 }}</ref> people living with dementia,<ref>{{Citation |last1=Blackler |first1=Alethea |title=Intuitive Interaction Framework in User-Product Interaction for People Living with Dementia |date=2020 |url=http://link.springer.com/10.1007/978-3-030-32835-1_10 |work=HCI and Design in the Context of Dementia |pages=147–169 |editor-last=Brankaert |editor-first=Rens |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-32835-1_10 |isbn=978-3-030-32834-4 |access-date=2022-10-24 |last2=Chen |first2=Li-Hao |last3=Desai |first3=Shital |last4=Astell |first4=Arlene |series=Human–Computer Interaction Series |s2cid=220794844 |editor2-last=Kenning |editor2-first=Gail|url-access=subscription }}</ref> and children.<ref>{{Cite journal |last1=Desai |first1=Shital |last2=Blackler |first2=Alethea |last3=Popovic |first3=Vesna |date=2019-09-01 |title=Children's embodied intuitive interaction – Design aspects of embodiment |url=https://www.sciencedirect.com/science/article/pii/S2212868918300552 |journal=International Journal of Child-Computer Interaction |language=en |volume=21 |pages=89–103 |doi=10.1016/j.ijcci.2019.06.001 |s2cid=197709773 |issn=2212-8689}}</ref>

Some have argued that aiming for "intuitive" interfaces (based on reusing existing skills with interaction systems) could lead designers to discard a better design solution only because it would require a novel approach and to stick with boring designs. However, applying familiar features into a new interface has been shown not to result in boring design if designers use creative approaches rather than simple copying.<ref>{{Cite journal |last1=Hurtienne |first1=J. |last2=Klockner |first2=K. |last3=Diefenbach |first3=S. |last4=Nass |first4=C. |last5=Maier |first5=A. |date=2015-05-01 |title=Designing with Image Schemas: Resolving the Tension Between Innovation, Inclusion and Intuitive Use |journal=Interacting with Computers |language=en |volume=27 |issue=3 |pages=235–255 |doi=10.1093/iwc/iwu049 |issn=0953-5438|doi-access=free }}</ref> The throwaway remark that "the only intuitive interface is the nipple; everything else is learned."<ref>{{cite web |url=http://www.greenend.org.uk/rjk/2002/08/nipple.html |title=The Only Intuitive Interface Is The Nipple |last=Kettlewell|first=Richard|publisher=Greenend.org.uk |access-date=2013-11-01 |url-status=live |archive-url=https://web.archive.org/web/20120130131229/http://www.greenend.org.uk/rjk/2002/08/nipple.html |archive-date=2012-01-30 }}</ref> is still occasionally mentioned. Any breastfeeding mother or [[lactation consultant]] will tell you this is inaccurate and the nipple does in fact require learning on both sides. In 1992, [[Bruce Tognazzini]] even denied the existence of "intuitive" interfaces, since such interfaces must be able to intuit, i.e., "perceive the patterns of the user's behavior and draw inferences."<ref>Tognazzini, B. (1992), ''Tog on Interface'', Boston, MA: Addison-Wesley, p. 246.</ref> Instead, he advocated the term "intuitable," i.e., "that users could intuit the workings of an application by seeing it and using it". However, the term intuitive interaction has become well accepted in the research community over the past 20 or so years and, although not perfect, it should probably be accepted and used.