2. Task Analysis in User- Centered Design Marti Hearst (UCB SIMS) SIMS 213, UI Design & Development February 2, 1999

3. Today l Why Task Analysis –Task Analysis vs. Software Engineering –Another overview l Creating scenarios –Define task analysis compoents –Put them together in scenarios l Using task scenarios in evaluating design

4. Task Analysis vs. Software Engineering l What is the difference between – user-centered design/task analysis –software design? l Both require –statements of what the system will do –hierarchical breakdown of tasks –specification of inputs, outputs, data flow, functionality

5. Why Task Analysis? l A difference in emphasis –There may be more than one way to implement some kind of functionality –User-centered perspective makes the designer consider what the users need and prefer –Optimize for the most common user tasks l Additional considerations –How easy to learn/retain knowledge of system –How easy to backup/fix mistakes –How well it solves users tasks/needs –Tutorials, context of use (lighting, interruptions), cognitive considerations

6. Different Users/Different Paths through the Data Structures user 1 user 2

7. Task Analysis Overview l Task Analysis: (Olsen 98) –Identify the goals and purposes of the prospective user community –Understand what users do to achieve those goals –Then design systems that help them better achieve those results. l Three outcomes: –A set of plausible scenarios of user behavior –Lists of information objects that users must have to accomplish their goals –Set of actions that users can take. l Then evaluation: –Frequency of use, importance of task in everyday practice –How interface fits within context of use

8. Student Course Enrollment: Helping the University Help Students Achieve their Goals enroll in sims 213 learn to build useful systems become successful IT manager achieve lifetime of success

9. Help Users Achieve Goals l Example: Course Enrollment Software –Typical software engineering concern: »how to sign up for sims 213: specify name, select course, select section, if full, try another section. –What if there is a conflict with the new section? How to resolve?

10. Helping Users Achieve Goals l Course Enrollment using User- Centered Design –Goal: satisfy program course requirements »Filter out already taken courses »Filter out undesirable profs »Indicate which courses not shown because pre- requisites not met (don’t just hide them) »Show when courses are next scheduled to be offered –Only the first would automatically be in the design spec of a non-user-oriented course- enrollment system –What about administrators needs?

11. Task-Centered Design l Create Scenarios –Find out »who users are »what tasks they need to perform –Create scenarios representing actual use l Design –Decide which users and tasks to support –Design based on these l Evaluation –Test interface by “walking through” it using scenarios –Do this before implementation use the following questions

12. Slide adapted from Ben Shneiderman Scenario Development l Characterize what happens when users perform typical tasks –First, collect info on who, what, when »interviews, ethnographic studies, surveys –Then, combine into scenarios l Tools for combining: –table of user communities vs tasks –table of task sequences –flowchart or transition diagram –videotape depicting scenario

13. E-Commerce Web Sites l Encourage and allow users to –shop –purchase –learn about the company l Compare toy shopping sites

14. Slide adapted from James Landay's Identification Questions l Who is going to use the system? l What tasks do they now perform? l What tasks are desired? l How are the tasks learned? l Where are the tasks performed? l What is the relationship between the user and the data?

15. Slide adapted from James Landay's Identification Questions l What other tools does the user have? l How do users communicate with each other? l How often are the tasks performed? l What are the (time) constraints on the task? l What happens when things go wrong?

16. What We Didn’t Ask l What is the system’s name? –see Dilbert l What tool is it implemented in? l Will the system be object-oriented? l What colors will it use?

17. Slide adapted from James Landay's Who? (User Profiles) l Role l Background l Skills l Habits and Preferences l Personal Characteristics

18. Who (E-Commerce) l Role –Parents –Gift-givers –Educators/Administrators (purchasing dept.) l Background –Have a credit card account –Know about toys –Reasonable Internet connection l Skills –Can use WWW basics –Know how to use credit card account

19. Who (E-Commerce) l Habits and Preferences –Browse leisurely vs. quick decision –Pricing concerns –Learning about products l Characteristics –Varying levels of patience –(BART ticket example -- varying heights)

20. Slide adapted from James Landay's Talk to Them l Find some real users –Parents/Gift Givers/Pre-school educators –Never shopped on Web/Occassional shopper/avid shopper l Talk to them –find out what they do –how would the system fit in?

21. Slide adapted from James Landay's Which Tasks? l For –Already existing practice –Enabling new functionality l Relative importance of tasks l Observe users –To see the unexpected

22. Slide adapted from James Landay's Which Tasks? (E-Commerce) l Existing Practice? –Browse/purchase in store –Browse/purchase from paper catalog –Purchase orders/Credit Cards/Cash –See ads for sales l New Functionality? –Price comparisons (shopbots) –View inventory levels –Check purchase with favorite watchdog group –“one-click” purchase –“view related items”

23. Which Tasks? (E-Commerce) l Let’s get more detailed –Isabelle is a mother of two. She browses the product descriptions to try to find an educational toy appropriate for a 7 year old. She finds a chemistry set and “places” it in her virtual shopping cart. She continues browsing the site, adding a Scrabble game for her 10-year-old, and a book for her 7-year-old to the cart. When she goes to “check out” she suddenly remembers she doesn’t need the Scrabble (they are getting a hand-me-down) and wants to check what the better business bureau says about the safety of the chemistry set before making the purchase. (It turns out ok.) Then she decides she also wants to send the same book to a friend for her daughter, gift-wrapped. She makes the purchase using a credit card.

24. Which Tasks? (E-Commerce) l Other sub-tasks that came up in that task: –take things out of shopping cart –order a quantity larger than 1 –send an item to another address –giftwrap only one item –check related information l What else might come up? –Item is back-ordered –Pay by installment/put item on hold –Some items must be purchased through a physical dealer –Ask for equivalent items that are on sale.

25. Make a Table: Who by What (adapted from Shneiderman 98)

26. Slide adapted from James Landay's How Often Do Users Perform the Tasks? l Frequent users remember more details l Infrequent users may need more prompting l Which function is performed –most frequently? –by which users? –optimize system for tasks that will improve perception of its performance

27. Augment Table with Percentages (What percentage of the is this task done by this person) (Numbers are only suggestive, adapted from Shneiderman 98 )

28. How often do Users Perform the Tasks? (E-Commerce) l Browsing l Purchasing l Comparing l Recommending l Getting recommendations

29. Next Time l Finish gathering information for scenarios l Characteristics of good scenarios l Putting it together for evaluation and design