Spring 2008 6.831 User Interface Design and Implementation 1Lecture 5: Task Analysis UI Hall of Fame or Shame?Fall 2006 6.831 UI Design and Implementation 2 Today’s candidate for the Hall of Fame & Shame is the Alt-Tab window switching interface in Microsoft Windows. This interface has been copied by a number of desktop systems, including KDE, Gnome, and even Mac OS X. For those who haven’t used it, here’s how it works. Pressing Alt-Tab makes this window appear. As long as you hold down Alt, each press of Tab cycles to the next window in the sequence. Releasing the Alt key switches to the window that you selected. We’ll discuss this example in class. Here are a few things to think about: - how learnable is this interface? - what about efficiency? - what kinds of errors can you make, and how can you recover from them?UI Hall of Fame or Shame?Fall 2006 6.831 UI Design and Implementation 3 For comparison, we’ll also look at the Exposé feature in Mac OS X. When you push F9 on a Mac, it displays all the open windows – even hidden windows, or windows covered by other windows – shrinking them as necessary so that they don’t overlap. Mousing over a window displays its title, and clicking on a window brings that window to the front and ends the Exposé mode, sending all the other windows back to their old sizes and locations. Today’s Topics• User analysis• Task analysis• Domain analysis• Requirements analysisSpring 2008 6.831 User Interface Design and Implementation 4 We’ve seen that UI design is iterative – that we have to turn the crank several times to achieve good usability. How do we get started? How do we acquire information for the initial design? Today’s lecture is about the process of collecting information about users and their tasks, which is the first step in user-centered design. We’ll talk about four key steps: User analysis: who is the user? Task analysis: what does the user need to do? Domain analysis: what is the context the user works in (the people and things involved)? Requirements analysis: what requirements do the preceding three analyses impose on the design?Know Thy User• Identify characteristics of target user population– Age, gender, culture, language– Education (literacy? numeracy?)– Physical limitations– Computer experience (typing?)– Motivation, attitude– Domain experience– Application experience– Work environment and other social context– Relationships and communication patternsSpring 2008 6.831 User Interface Design and Implementation 5 The reason for user analysis is straightforward: since you’re not the user, you need to find out who the user actually is. User analysis seems so obvious that it’s often skipped. But failing to do it explicitly makes it easier to fall into the trap of assuming every user is like you. It’s better to do some thinking and collect some information first. Knowing about the user means not just their individual characteristics, but also their situation. In what environment will they use your software? What else might be distracting their attention? What is the social context? A movie theater, a quiet library, inside a car, on the deck of an aircraft carrier; environment can place widely varying constraints on your user interface. Other aspects of the user’s situation include their relationship to other users in their organization, and typical communication patterns. Can users ask each other for help, or are they isolated? How do students relate differently to lab assistants, teaching assistants, and professors? Multiple Classes of Users• Many applications have several kinds of users– By role (student, teacher)– By characteristics (age, motivation)• Example: Olympic Message System– Athletes– Friends & family– Telephone operators– SysadminsSpring 2008 6.831 User Interface Design and Implementation 6 Many, if not most, applications have to worry about multiple classes of users. Some user groups are defined by the roles that the user plays in the system: student, teacher, reader, editor. Other groups are defined by characteristics: age (teenagers, middle-aged, elderly); motivation (early adopters, frequent users, casual users). You have to decide which user groups are important for your problem, and do a user analysis for every class. The Olympic Message System case study we saw in a previous lecture identified several important user classes by role.Personas• A persona is a fictitious character used as a specific representative of a user class– Yoshi is a 20-year-old pole vaulter from Tokyo who speaks some English– Bob is an IBM sysadmin in New York– Fritz is the 50-year-old father of a German swimmer• Advantages– Convenient handle for talking about user classes– Focuses on a typical user, rather than an extreme– Encourages empathySpring 2008 6.831 User Interface Design and Implementation 7 One popular technique for summarizing user classes is to give each user class a fictional representative, with typical characteristics and often a little back story. These representatives are called personas. Personas are useful shorthand for a design group; you can say things like “let’s think about how Yoshi would do this”, rather than a mouthful like “non-English-speaking athlete.” They also help focus attention on typical members of the user class, rather than extremes. And by putting a human face on a user class, albeit an imaginary one, they can encourage you to have more empathy for a user class that’s very different from your own. (Alan Cooper, The Inmates are Running the Asylum, 1999). How To Do User Analysis• Techniques– Questionnaires– Interviews– Observation• Obstacles– Developers and users may be systematically isolated from each other• Tech support shields developers from users• Marketing shields users from developers– Some users are expensive to talk to• Doctors, executives, union membersSpring 2008 6.831 User Interface Design and Implementation 8 The best way to do user analysis is to find some representative users and talk to them. Straightforward characteristics can be obtained by a questionnaire. Details about context and environment can be obtained by interviewing users directly, or even better, observing them going about their business, in their natural habitat. Sometimes it can be hard to reach users. Software companies can erect artificial barriers between users and
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