Usability Teppo Räisänen

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 daily users in Finland an usability issue that costs 20 seconds of time / instance of use ~ 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: 3RLb8