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Usability. Teppo Räisänen http://www.oamk.fi/~teraisan/ Teppo.raisanen@oamk.fi. What Is Usability?. How easy is it for a user of a product to achieve his/her objectives Interaction between a human being and a machine HCI (Human-Computer Interaction)
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Usability Teppo Räisänen http://www.oamk.fi/~teraisan/ Teppo.raisanen@oamk.fi
What Is Usability? • How easy is it for a user of a product to achieve his/her objectives • Interaction between a human being and a machine • HCI (Human-Computer Interaction) • Usability is not restricted to computer-based products
What Is Usability? • Usability of a procuct can be good or poor • Often small changes in user interface can result in much better usability: • Windows tool tips • ”Push” sticker in a door • Changes are often visual clues
Subcategories of Usability • Learnability • Memorability • Effectiveness • Robustness • Enjoyability
Learnability/Memorability • The ease of becoming effective for a new user • Similar behaviour in similar situations • Predictability of response • Generalizability – ability to extend current knowledge to other situations
Effectiveness/Robustness • Recoverability – once observed errors are corrected • Responsiveness – the speed of communication • Task completeness – System supports users tasks as how he/she percieves them
Enjoyability • The level of satisfaction • Very user-dependent as a concept • Often mentioned ’Intuitive user interface’ • Something new the resembles something familiar • Is based on an individual’s earlier experiences
Usability As a Discipline • Usability research is centered around • Qualities that have an effect on good/poor usability • Methods that can be used in evaluating product’s usability • Methods that can be used in designing products of good usability
Usability As a Discipline • Usability is very interdisciplinary • Psychology • Engineering • Arts • Linguistics • An usability expert should be a combination of a psychologist, an engineer and an artist
Usability As a Discipline • Traditionally resarch of usability was restricted to user interfaces • However many products, that had sophisticated user interfaces failed • Usability is also affected by qualities like product’s structure and responsiveness
ISO 9241 • International Organization for Standardization has defined usability as a wholeness, which desribes • How easily certain users can • use tools available for them • to perform certain tasks • in a particular environment
Why Usability Is Important? • Modern development environments have made programming work easier • Computer-based products have become more and more sophisticated • Consumers have more and more products to choose from • Usability has become an important competitive weapon
Why Usability Is Important? • According to research usability was estimated to be one of 6 most important skills required within software development • Usability is strongly connected to requirements spesification phase of software development
Why Usability Is Important? • Usability can also have a huge economical impact: • If a software has • 300 000 daily users in Finland • an usability issue that costs 20 seconds of time / instance of use • ~600 000 hours (~25300 days) of working time is lost each year
Usability & Software Projects • Usability issues are still often neglected • Eg. according to a study a large portion of health care related problems in Finland originate from poor usability of software • User-centered design methods are seen as heavy and time (= money) consuming
Usability & Software Projects • Usability should be taken as a natural part of development process • Usability should also be evaluated • Usability testing plan • Verification of goals accomplished • Corrections and updates if needed • Careful documentation of usability issues and solutions is important
Usability exercise • In teams of two • Discuss about the usability of a laptop trackpad • How could you improve it?
Usability & Software Projects • Watch the video: • http://www.youtube.com/watch?v=T63BDr3RLb8