1. 1 User Studies: Surveys and Continuing Assessment Lecture 5

2. CS774 – Spring 20062 Case Study: One-Or-More Buttons Task: Good control that gives the user a "one or more, but not none" selection  Cross between radio buttons and check boxes  Select as many as want, but always keep at least one selected from Bruce "TOG" Tonazzini's TOG on Interface, 1991

3. CS774 – Spring 20063 Approaching the Problem Guidelines for expanding an interface  If it ain't broke real bad, don't fix it  Build on existing visual/behavioral language  Invent new objects, with new appearances, for new behavior  When possible, evolve objects, rather than starting from scratch  Make changes clearly visible  Interpret users' responses consistently  Multiplex meanings

4. CS774 – Spring 20064 Constraints People have to figure out how to use the control on their own, first time out Appearance reflect marriage between radio buttons and check boxes

5. CS774 – Spring 20065 Ten Steps for User Testing on the Cheap 1. Introduce yourself 2. Describe the purpose of the observation (in general terms) Stress you want to find problems in the product 3. Tell the participant that it's OK to quit at any time 4. Talk about the equipment in the room 5. Explain how to "think aloud."

6. CS774 – Spring 20066 Ten Steps for User Testing on the Cheap 6. Explain that you will not provide help 7. Describe the tasks and introduce the product 8. Ask if there are any questions before you start; then begin the observation 9. Conclude the observation 10. Use the results

7. CS774 – Spring 20067 The Paper Test

8. CS774 – Spring 20068 Next Iteration Response to first iteration More designs Testing  Thought it looked like an icky bug  X meant it was inactive (cancelled)  Thought rule was that you had to use a particular English

9. CS774 – Spring 20069 3 rd Iteration Next design: Test 5 subjects  None develop superstitious rule  The object work! But…  Prototypes started with at least two buttons on  If they go locked up, hound them until they try clicking the immutable button

10. CS774 – Spring 200610 Peer Design Review What was the funny looking line? New design:  The superstitious rule came back Solving the superstitious rule  Mimic mercury: Pressing the only button turned on will cause it to turn off and the button below to turn on Test: 11 year old son immediately knows the rule

11. CS774 – Spring 200611 Final Design Validation Testing  5 people 2 nine year olds woman who uses a Mac 2 hours per week woman who uses a Mac 2 hours per day self-identified power-user  All learned rule within 15 seconds

12. CS774 – Spring 200612 Survey Instruments  Written user surveys are a familiar, inexpensive and generally acceptable companion for usability tests and expert reviews. Keys to successful surveys  Clear goals in advance  Development of focused items that help attain the goals. Survey goals can be tied to the components of the Objects and Action Interface model of interface design. Users could be asked for their subjective impressions about specific aspects of the interface such as the representation of:  task domain objects and actions  syntax of inputs and design of displays.

13. CS774 – Spring 200613 Surveys (cont.) Online surveys avoid the cost of printing and the extra effort needed for distribution and collection of paper forms. Many people prefer to answer a brief survey displayed on a screen, instead of filling in and returning a printed form,  although there is a potential bias in the sample.

14. CS774 – Spring 200614 A cceptance Test For large implementation projects, the customer or manager usually sets objective and measurable goals for hardware and software performance. If the completed product fails to meet these acceptance criteria, the system must be reworked until success is demonstrated. Rather than the vague and misleading criterion of "user friendly," measurable criteria for the user interface can be established for the following:  Time to learn specific functions  Speed of task performance  Rate of errors by users  Human retention of commands over time  Subjective user satisfaction

15. CS774 – Spring 200615 A cceptance Test (cont.) In a large system, there may be eight or 10 such tests to carry out on different components of the interface and with different user communities. Once acceptance testing has been successful, there may be a period of field testing before national or international distribution. Yes or no decision - is it good enough to release?

16. CS774 – Spring 200616 Evaluation During Active Use Interviews and focus group discussions Continuous user-performance data logging Online or telephone consultants Online suggestion box or e-mail trouble reporting Discussion group and newsgroup

17. CS774 – Spring 200617 Controlled Psychologically-oriented Experiments Scientific and engineering progress is often stimulated by improved techniques for precise measurement. Rapid progress in the designs of interfaces will be stimulated as researchers and practitioners evolve suitable human-performance measures and techniques.

18. CS774 – Spring 200618 Controlled Psychologically-oriented Experiments (cont.) The outline of the scientific method as applied to human-computer interaction might comprise these tasks:  Deal with a practical problem and consider the theoretical framework  State a lucid and testable hypothesis  Identify a small number of independent variables that are to be manipulated  Carefully choose the dependent variables that will be measured  Judiciously select subjects and carefully or randomly assign subjects to groups  Control for biasing factors (non-representative sample of subjects or selection of tasks, inconsistent testing procedures)  Apply statistical methods to data analysis  Resolve the practical problem, refine the theory, and give advice to future researchers

19. CS774 – Spring 200619 Controlled Psychologically-oriented Experiments (cont.) Controlled experiments can help fine tuning the human-computer interface of actively used systems. Performance could be compared with the control group. Dependent measures could include performance times, user- subjective satisfaction, error rates, and user retention over time.