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usability1.ppt usability1.ppt Presentation Transcript

    • Plan for the next 6 weeks:
    • > The case for usability – Usability testing 1
    • Usability testing 2
    • Today: Usability testing 3
    • Heuristic analysis 1
    • Heuristic analysis 2
    • Accessibility
    106CR: Designing for Usability
  • PLEASE READ:
    • Benyon, Turner and Turner
    • Chapter 12
    • PLEASE ALSO READ:
    • The downloadable PDF files on the 106CR Website
    • PLEASE ALSO LOOK AT
    • http://www.webpagesthatsuck.com/
  • User Friendly 8-(
    • Never, Never, Never
    • Instant expulsion from the course, etc…
    • Software cannot be friendly, it is not sentient.
    • This is called ANTHROPOMORPHISM
    • Welcome to Usability Club….
  • In usability club we don’t say ‘user friendly’ we say ‘USABLE’
    • To claim that an interface is ‘user friendly’ is subjective and not testable.
    • To claim that an interface is USABLE requires that we measure ‘usability’ with some predetermined metrics/measures.
    • This is much more scientific (and legally sound too)
  • The p rinciples of usable design suggest that there are more specific concepts that can be measured. We need to ensure that our ‘measuring method’ is appropriate to the purpose of the interface or application that we are testing. Even so, “usability” is a very general concept…
  • One definition of usability
    • ISO 9241 (part 11) 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”
    • … we could add ‘learnability ’ to this list.
    • Effectiveness: Can you actually do a specified task?
    • Efficiency: Can you do it quickly, without getting bored or frustrated?
    • Satisfaction: Is it fun, or at least pleasant to use?
    • Learnability: Can you use it without constantly reaching for the manual or asking for help.
    • Each of these concepts needs a different measuring method. E.g:
    • - Efficiency: Time to complete task
    • - Effectiveness: percentage of tasks completed in test.
    • - Satisfaction: Rating the application in a questionnaire.
    • Which measuring concept would be most important for the following?
      • A Playstation game
      • A data entry screen for a call centre worker – capturing caller name / address details.
      • A media player in a mobile phone
      • Bank ATM machine
      • CUOnline calendar
    • Note: effectiveness is essential for all of these…
  • Usability Metrics: Task completion Number of errors made Time taken Number of times frustration is expressed Ratio of optimum click path to actual click path in a website (e.g. navigation should take 2 clicks but user completed task in 11 clicks. Many others
    • “ The lack of usability of software and the poor design of programs are the secret shame of the [software] industry. … Computing professionals themselves should take responsibility for creating a positive user experience. Perhaps the most important conceptual move to be taken is to recognize the critical role of design, as a counterpoint to programming, in the creation of computer artifacts.”
    • Mitch Kapor in ‘Bringing Design to Software’ (Edited by Terry Winograd)
    Usability: Why should we care?
    • Three approaches to understanding the importance of usability
    • The Paradigm Shift
    • The case for Usability
    • Constraints on implementing Usability
    • 1: Paradigm Shift
    • In the last 25 years the focus in software design has moved from:
    • Fitting the user to the interface
    • to
    • Fitting the interface to the ‘person’
    • 25 years ago - Computing was a ‘specialist industry’ producing ‘specialist tools’
    • Required Mathematics / Computing graduates.
    • Paradigm Shift
    • Change in computer use:
    • Mainframes in 1970’s ………..... Expert users
    • Domestic PC, Mobiles, TV’s….. non-expert users
    • Proportionally more of the code in a computer application is devoted to the user interface - (McIntyre et al 1990)
          • 20% in 1980 (command line)
          • 50% in 1990 (GUI)
          • about 80 - 90 % in web design now
    • Paradigm Shift
    • Devices are now used in a much broader set of contexts:
    • Globalisation - broadening the device market across the planet.
    • Localisation - culturally specific interfaces (particularly the web – how many localised amazon sites are there? .com / .co.uk / .de / .es).
    • Personalisation – the customisability and ‘preferences setting’ that users expect from their devices.
    • Interoperability – growing expectations that devices will work together.
    • Is usability a new name for an old practice?
    • We find concerns about the intelligibility of interfaces in disciplines as broad as:
    • Human Computer Interaction
    • Psychology
    • Graphic Design
    • Cultural Studies
    • … However, these disciplines are concerned with the understanding of human action at an explanatory level (the WHY? Question) .
    • Research output from these fields often gives very few clues as to ‘what to do’ with the information they discover.
    • Usability is focused on ACTION.
    • Not so concerned with WHY an interface fails but WHAT is to be changed to make it work: Action oriented research:
    • Field observation / testing
    • Engagement with users
    • Prototype building
    Commercial Academic Focus on practical solutions Focus on theoretical explanation How Why Usability HCI
    • Making a Case for Usability
    • The Economic Case
    • The Competitive Case
    • The Legal and Ethical Case
    • The case for Usability
    • The Economic Case
    • Companies in the global software industry are finding it increasingly difficult to compete on functionality or price.
      • Functionality: With the exception of Patents (which have always been shaky vehicles for competitive advantage in the software industry) Many vendors can offer similar products.
      • Price: The globalisation of the industry has meant that price levels for similar products has started to equalise (interesting case of Linux / open source)
    • In the absence of competition at the levels of functionality and price – vendors start to compete at the level of ‘non-functional’ features such as Usability, aesthetics or lifestyle appeal (Think about Apple…)
  • The Economic Case: Example E-Commerce Usable Websites: Increase likelihood of customers completing a transaction online Customers who can find what they're looking for easily and quickly will be more likely to conduct a transaction Increase customer retention and satisfaction. Ease of use also builds customer loyalty and thus greater profits over time Reduce the costs associated with support, documentation, and training. A usable site will mean that less (telephone) support or documentation and training is required.
  • The Competitive Case Unlike ‘real-world’ shopping, where switching between suppliers is a matter of considerable effort, in e-commerce: Competitive sites are just a few clicks away - for a customer who is having a negative experience with a site. Customer experience is a key differentiator for business-to-consumer (B2C) websites. Research shows that a negative experience with an e-commerce site means the loss of an individual customer forever (Every, Goodhead 2003)
  • The Legal and Ethical case DDA – Disability discrimination Act (UK) – originally introduced to promote ‘physical’ access to buildings is being revised (partly by case law, partly by legislation) to include access to electronic or ‘virtual’ resources. Being locked out of a bookstore because it does not have wheelchair access is increasingly equated to being ‘locked’ out of a ‘virtual bookstore’ because it does not provide basic facilities for accessibility software such as screen readers. However, there is also a more fundamental professional and ethical dimension than the purely legal one: Poor accessibility and usability is simply not polite
  • Cost of usability According to a variety of sources (Nielsen, Usable.net) usability has a cost-benefit ratio of anywhere from 1:10 - 1:100. That is, for every Pound spent on implementing usability the site owner will realise a benefit between £10 and £100 in increased sales.
    • Constraints on implementing Usability
    • Design Inertia
    • Design traditions and perspectives
    • Legal, contractual and process constraints
  • Constraints on implementing Usability Design Inertia Standards and traditions ‘enshrine’ design approaches and objects – making it very difficult to ‘revolutionise’ design on the basis of usability. (the costs are too great, the staff are already trained in the ‘old system’) Example: The QWERTY keyboard.
    • Design traditions and perspectives
    • Different types of designer ask very different types of question:
    • Software perspective - System / technical design - how hardware and software fit together to produce a functional system. Concentration is on functionality.
    • System centred design questions:
      • What can be built on this platform?
      • What can I create from the available tools?
      • How do I as a programmer think the system should be designed?
    • Design traditions and perspectives
    • Different designers ask very different types of question:
    • Graphic design - often used to produce a sense of ‘style’ or corporate identity. Concentration is on aesthetics / Look and feel.
    • Graphic centred design questions:
      • How do I create a good looking site?
      • What can I create from the available tools?
      • How do I as a graphic designer think the system should be designed?
      • Neither system design or graphic design approaches consider usability as a primary concern
    • The Missing questions….
    • … . Are user centred design questions:
      • What do users want to do with this software?
      • How can I make this software easier to use?
      • How do I make the software usable by the widest number of people?
    • User Centred Design?
    • "To users, the user interface is the system.“ (Deborah Hix and H. Rex Hartson, " Developing User Interfaces", 1993)