1. Interpretive Evaluation Agenda Simple user modeling Interpretive Evaluation - Motivation - Methods Ethnography Fitt’s Law

2. Fall 2002CS/PSY 67502 Simpler User Modeling How do attributes of users influence the design of user interfaces? Are there some design guidelines that we can derive from different attributes?

3. Fall 2002CS/PSY 67503 User Profiles Attributes:  attitude, motivation, reading level, typing skill, education, system experience, task experience, computer literacy, frequency of use, training, color-blindness, handedness, gender,… Novice, intermediate, expert

4. Fall 2002CS/PSY 67504 Motivation User  Low motivation, discretionary use  Low motivation, mandatory  High motivation, due to fear  High motivation, due to interest Design goal  Ease of learning  Control, power  Ease of learning, robustness, control  Power, ease of use

5. Fall 2002CS/PSY 67505 Knowledge & Experience Experience tasksystem  lowlow  highhigh  lowhigh  highlow Design goals  Many syntactic and semantic prompts  Efficient commands, concise syntax  Semantic help facilities  Lots of syntactic prompting

6. Fall 2002CS/PSY 67506 Job & Task Implications Frequency of use  High - Ease of use  Low - Ease of learning & remembering Task implications  High - Ease of use  Low - Ease of learning System use  Mandatory - Ease of using  Discretionary - Ease of learning

7. Fall 2002CS/PSY 67507 Evaluation Predictive  Discount Usability (Mon)  Cognitive Modeling-GOMS family (Wed)  Cognitive Modeling-contextual (next Mon) Interpretive (today) User testing (later)

8. Fall 2002CS/PSY 67508 Approaches Experimental (Lab studies, quantitative)  Typically in a closed, lab setting Manipulate independent variables to see effect on dependent variables Naturalistic (Field studies, qualitative)  Observation occurs in “real life” setting Watch process over time “Ecologically valid”

9. Fall 2002CS/PSY 67509 Interpretive Evaluation Experimental: Formal and objective Interpretive: More subjective  Concerned with humans, so no objective reality  Sociological, anthropological approach Users involved, as opposed to predictive approaches

10. Fall 2002CS/PSY 675010 Beliefs Sees limitations in scientific hypothesis testing in closed environment  Lab is not real world  Can’t control all variables  Context is neglected  Artificial, short tasks

11. Fall 2002CS/PSY 675011 IE Methods A number of different methods or techniques in this area exist  Ethnography Our main focus  Contextual inquiry More specific form of ethnography with a focus on asking questions  Field study Common notion, often equated with ethnography  Observational study Much more informal, just watching users  …

12. Fall 2002CS/PSY 675012 Ethnography Deeply contextual study Immerse oneself in situation you want to learn about (anthropological and sociological roots)  Observing people in their cultural context Interpretation of data is primary Behavior is meaningful only in context

13. Fall 2002CS/PSY 675013 Philosophy Argues that formal environment of controlled study is artificial --- Experimenter wields “power” over subject So … get into working environment of user -> Interpretation is primary, rather than data

14. Fall 2002CS/PSY 675014 Objectives Understanding the user  Understand goals and values  Understand individual’s or group’s interactions within a culture  Try to make tacit domain knowledge explicit  Do this in an unbiased fashion  For UI designers: Improve system by finding problems in way it is currently being used

15. Fall 2002CS/PSY 675015 Techniques In person observation Audio/video recording Interviews “Wallow in the data”

16. Fall 2002CS/PSY 675016 Observation is Key Carefully observe everything about users and their environment Think of describing it to someone who has never seen this activity before What users say is important, but also non- verbal details

17. Fall 2002CS/PSY 675017 Observations Things of interest to evaluator  Structure and language used in work  Individual and group actions  Culture affecting work  Explicit and implicit aspects of work Example: Office work environment  Business practices, rooms, artifacts, work standards, relationships between workers, managers, …

18. Fall 2002CS/PSY 675018 Interviews Important Have a question plan, but keep interview open to different directions Be specific Create interpretations together with users At end, query “What should I have asked?” Record interviews

19. Fall 2002CS/PSY 675019 Steps 1. Preparation  Understand organization policies and work culture  Familiarize yourself with system and its history  Set initial goals and prepare questions  Gain access and permission to observe & interview 2. Field study  Establish rapport with users  Observe/interview users in workplace and collect all different forms of data  Follow any leads that emerge from visits  Record the visits Rose et al ‘95

20. Fall 2002CS/PSY 675020 Steps 3. Analysis  Compile collected data in numerical, textual and multimedia databases  Quantify data and compile statistics  Reduce and interpret data  Refine goals and process used 4. Reporting  Consider multiple audiences and goals  Prepare a report and present findings

21. Fall 2002CS/PSY 675021 One Technique Affinity Diagram Process  Write down each quote/observation on a slip of paper  Put up on board  Coalesce items that have affinity If they are saying similar things about an issue  Give names to different groups (colors too)  Continue grouping subgroups  A hierarchy will be formed

22. Fall 2002CS/PSY 675022 Why Useful? Can help designer gain a rich and true assessment of user needs  Help to define requirements Uncovers true nature of user’s job  Discovers things that are outside of job description or documentation Allows you to play role of end-user  Can sit in when real users not available Open-ended and unbiased nature promotes discovery  Empirical study and task analysis are more formal – ethnography may yield more unexpected revelations

23. Fall 2002CS/PSY 675023 Types of Findings Can be both  Qualitative Observe trends, habits, patterns, …  Quantitative How often was something done, what per cent of the time did something occur, how many different …

24. Fall 2002CS/PSY 675024 Drawbacks Time required  Can take weeks or months Scale  Most use small numbers of participants just to keep somewhat manageable Type of results  Highly qualitative, may be difficult to present and use Acquired skill  Identifying and extracting “interesting” things is challenging

25. Fall 2002CS/PSY 675025 Ethnomethodology Concurrent/informed ethnography  Study is being done in conjunction with a system being developed  + Helps keep focus on user throughout design  - Requires lots of time and coordination

26. Fall 2002CS/PSY 675026 Cooperative Evaluation User is viewed as collaborator in evaluation, not a subject  “Friendly approach” Relaxed version of think-aloud  Evaluator and participant can ask each other questions

27. Fall 2002CS/PSY 675027 CE Methods Seeks to detect errors early in a prototype Experimenter uses tasks, also talks to participant throughout, asks questions

28. Fall 2002CS/PSY 675028 Low Level Models Fitt’s Law  Models movement times for selection tasks Basic idea: Movement time for a well- rehearsed selection task  Increases as the distance to the target increases  Decreases as the size of the target increases

29. Fall 2002CS/PSY 675029 Components ID - Index of difficulty ID = log 2 ( 2A/W ) bits result Both quantities are distances so unitless result width tolerance of target distance to move

30. Fall 2002CS/PSY 675030 Components MT - Movement time MT = b * ID or MT = a + b*ID MT is a linear function of ID

31. Fall 2002CS/PSY 675031 Original Experiment 1-D AW

32. Fall 2002CS/PSY 675032 Exact Equation Run empirical tests to determine a and b in MT = a + b*ID Will get different ones for different input devices and ways the device is used MT ID

33. Fall 2002CS/PSY 675033 Common Equation MT = a + b log 2 (A/W + 1) Provides useful numbers

34. Fall 2002CS/PSY 675034 Questions What do you do in 2D? Where can this be applied in user interface design?