Scenario-Based Usability Engineering for User Interface Design

1. CS 3724Lecture 2:Scenario-Based Design Section 1 CRN 11499 TTh 5:00-6:15 206 McB

2. Today’s Agenda • Thinking about the teamTerm project • From HCI to Usability Engineering • Measuring usability • Making tradeoffs • Scenarios • The Scenario-Based UE Method • Scenarios • claims • History and Future of HCI

3. Projects • Information Visualization • College of Engineering Community Information

4. What is HCI? • The Human • Single user, groups, I/O channels, memory, reasoning, problem solving, error, psychology • The Computer • Desktop, embedded system, data entry devices, output devices, memory, processing • The Interaction • Direct/indirect communication, models, frameworks, styles, ergonomics

5. Why Usability Engineering? • Waterfall models of development do not work • Too many unknowns (Brooks: No Silver Bullet) • Need an iterative discovery-oriented process • But at the same time need to manage it • Demands well-defined process with metrics • Specifying usability goals as objectives • Assessing and redesigning to meet these objectives • Manage usability as a quality characteristic, much like modularity or nonfunctional requirements

6. How Should We Measure Usability? • Bottom line is whether the users got what they wanted • Practically speaking, need to break this down so that we can operationalize our objectives • Our textbook definition: The quality of an interactive computer system with respect to ease of learning, ease of use, and user satisfaction • Can the users do what they want to do in a comfortable and pleasant fashion?

7. A Brief Digression…. • Users, clients, and customers are not necessarily the same -- and • Better usability is not the same as a better selling product… … but more about actors and tradeoffs in a little while.

8. User Interface Metrics • Ease of learning • Ease of use • User satisfaction Not “user friendly”

9. Scenarios in UE:A Simple Example A problem scenario describing current situation: Marissa was not satisfied with her class today on gravitation and planetary motion. She is not certain whether smaller planets always move faster or how a larger or denser sun would alter the possibilities for solar systems. She stays after class to speak with Ms. Gould, but she isn’t able to pose these questions clearly, so Ms. Gould suggests that she re-read the text and promises more discussion tomorrow.

10. A design scenario describing our initial vision: Marissa , a 10th-grade physics student, is studying gravity and its role in planetary motion. She goes to the virtual science lab and navigates to the gravity room. In the gravity room, she discovers two other students, Randy and David, already working with the Alternate Reality Kit, which allows students to alter various physical parameters (such as the universal gravitational constant) and then observe effects in a simulation world. The three students, each of whom is from a different school in the county, discuss possible experiments by typing messages from their respective personal computers. Together they build and analyze several solar systems, eventually focusing on the question of how comets can disrupt otherwise stable systems. They capture data from their experiments and display it with several visualization tools, then write a brief report of their experiments, sending it for comments to Don, another student in Marissa’s class, and Mr. Arkins, Randy’s physics teacher.

11. Scenario Elements • Setting (where? when?) • Actors (who?) • Task goals (why?) • Plans (how do they plan to accomplish it?) • Actions (what do we see the actors do?) • Events (system response) • Evaluation (is that what the user wanted?)

12. ANALYZE analysis of stakeholders, field studies claims about current practice Problem scenarios DESIGN Activity scenarios metaphors, information technology, HCI theory, guidelines iterative analysis of usability claims and re-design Information scenarios Interaction scenarios PROTOTYPE & EVALUATE summative evaluation formative evaluation Usability specifications

13. Tradeoffs • How to decide between paths? • Problem solving • Use a method (optimize, random selection, etc.) • Restate problem / solution space • Examples? • A Method (the SBD method): • Identify tradeoffs • Choose based on design goals • Track tradeoffs for rationale

14. Tradeoffs and SBD • Design by definition is invention, creativity • Never just one approach, never one correct answer • BUT some answers are demonstrably better • Interactive system design tremendously complex • Many interdependencies, eg schedule, cost, competitive advantage, local expertise, ... • Users and their needs are one large set of dependencies • Tradeoffs are useful in analyzing these relations • Here, we focus on tradeoffs affecting users’ experiences • Guides design thinking, also serves as design rationale

15. Learning SBD — By Example • Virtual science fair as a case study • Complement to real world physical science fairs • Goal is to extend interactions across time & space • Cumulative, illustrates activities at each phase • Detailed examples of the methods used in projects • Use as a model for group materials & analyses • Many details specific to this example • E.g., collaboration, community network, education

16. SBD Method:Scenarios and Claims • Scenarios convey what actors are like, what forces influence their behavior • Claims elaborate on scenarios, explaining how and why a feature has impacts • Claims analysis documents by isolating the most important features

17. SBD Method:Scenarios • Stories of people and their activities, sometimes includes computer use, always includes goals • Typical elements of the story are: • A setting • One or more actors or agents • An orienting or motivating goal or objective • Mental activity, plans or evaluation of behavior • A “storyline” sequenced by actions and events • Emphasis on use, i.e., people’s needs, expectations, actions, and reactions

18. SBD Method: Claims (see pgs 73-4)

19. Before we move on… • From HCI to Usability Engineering • Measuring usability • Making tradeoffs • Scenarios • The Scenario-Based UE Method • Scenarios • claims

20. Myth The user interface is tacked on at the end of the project.

21. The History of Computing Professional programmers, “software psychology” 1960’s Business professionals, mainframes, command-line 1970’s Large, diverse user groups, “the computer for the rest of us” 1980’s World Wide Web and more, information access & overload 1990’s Ubiquitous computing, diversity in task, device, … 2000+

22. … as seen by the Users Professional programmers, “software psychology” 1960’s Business professionals, mainframes, command-line 1970’s Large, diverse user groups, “the computer for the rest of us” 1980’s World Wide Web and more, information access & overload 1990’s Ubiquitous computing, diversity in task, device, … 2000+

23. History of HCI • Vannevar Bush, 1945 “As We May Think” • Vision of post-war activities, Memex • “…when one of these items is in view, the other can be instantly recalled merely by tapping a button”

24. History of HCI • JCR Licklider, 1960 “Man-Computer Symbiosis” • Tightly coupled human brain and machine, speech recognition, time sharing, character recognition

25. History of HCI • Douglas Engelbart, 1962 “Augmenting Human Intellect: A Conceptual Framework” • In 1968, workstation with a mouse, links across documents, chorded keyboard

26. XEROX (PARC) Alto and Star Windows Menus Scrollbars Pointing Consistency OOP Networked Apple LISA and Mac Inexpensive High-quality graphics 3rd party applications History of HCI

27. Large displays Small displays Peripheral displays Alternative I/O Ubiquitous computing Virtual environments Augmented Reality Speech recognition Multimedia Media space Artificial intelligence Software agents Games ... History (and future) of HCI

28. Scott McCrickard Doug Bowman Chris North Manuel Perez Deborah Tatar Steve Harrison Grad students & HCI Center researchers HCI at VT

29. Where Were We? • teamTerm project • From HCI to Usability Engineering • Measuring usability • Making tradeoffs • Scenarios • The Scenario-Based UE Method • Future of HCI • For Next Week… • Read UE Chapter 2 • Due (Thurs): Homework 1 • Due (Thurs): Team selection of project • MEET WITH YOUR TEAM !!!!