Evaluating Touch Gesture Usability

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Presentation slides from Usability Professionals Association Conference (UPA 2010) in Munich, May 26 2010. Please email me for more context and details.


<ul><li> 1. Evaluating Touch Gesture Usability Kevin Arthur SynapticsUPA 2010 1 </li></ul> <p> 2. 2 3. Multi-Finger TouchPad GesturesTwo-Finger Two-Finger Three-FingerPinch Zoom Rotate FlickTwo-Finger Two-Finger Three-FingerScroll Pivot RotatePress 3 4. Motivation for Testing Gestures Formative usability tests for feedback todevelopersAudience Summative and competitive usabilitytests for sales, OEM partners Need for repeatable procedures Do users understand the gestures?Questions Can users successfully perform thegestures? Are gestures satisfying to use? Holistic evaluation; test with users in arealistic scenario on a working system Context Different from pure data collection fortesting gesture recognizer offline 4 5. Important Properties of Gestures Gestures must be taught; testing the Lack of Affordances documentation is important Performance is not always predictableNondeterministic Recognition trade-offs exist between and Interdependentgestures in same parameter space Gestures should be evaluated as a setInterface TouchPads primary use is still for pointing and scrolling; gesturesOverloadingshouldnt interfere User Variation Hand size, long fingernails 5 6. Phases in Performing a Gesture Introduction through Exposuredocumentation or prior use Initial touch contact and motionRegistration for gesture recognition Gesture is registered and locked in mode switch Continuation Dynamic phase with relaxed motion requirementsTermination End position, fingers lifting 6 7. Test Framework StepObjectiveAssess understanding, help 1Gesture Introduction materials [Exposure phase]Familiarization and 2 Train to basic performancePractice Task [All phases] Obtain rates of correct and incorrect gesture recognition 3Accuracy Task [Registration phase]Assess satisfaction, ease of useSatisfaction Questionnaire 4and Debrief[All phases] 7 8. Gesture Introduction Simulate new user experience Out of box experiencematerial Help videos Try the gesture until success If no success, moderatorassists8 9. Familiarization and Practice Tasks: Pinch ZoomZoom in on the South Residences, near the top of the map, and find the building called The Knoll. Zoom all the way in on The Knoll and then zoom all the way back out. 2000 2000 pixels or higher. Approximately five pinch-zooms required.9 10. 10 11. Flick and Rotate 1. Use the rotate gesture to make the image upright. 2. Type the images title into the caption field and press Enter. 3. Use the flick gesture to go to the next image. 11 12. Flick and Rotate12 13. Accuracy TaskUser performs a set number of gesture attemptsModerator records table of system responses. Example: NoMisrecognized Other/Gesture Correct ResponseAs Pinch As Rotate NotesPinch Zoom 7 2 -1InPinch Zoom 8 2 -0 Out requiresRotate 6 3 1 -too large a ClockwisemotionRotateCounter- 7 1 2 -clockwise 13 14. Accuracy Results Unified Measure 100% 90% 80% 70% 60% 50%Misrecognized 40%No Response 30%Correct 20% 10%0% PinchPinch Rotate CW Rotate AverageZoom In Zoom OutCCW 14 15. Accuracy Results, Competitive Study System A System BAverage Correct 82%Average Correct 89% 100%100% 90%96 90%9496 9490 8880% 80%8582 83 70% 70%73 60% 60% 6150% 50% 40% 40% 30% 30% 20% 20% 10% 10%0%0% 2F Pinch 2F Rotate 3F Flick 3F Flick 2F Scroll2F Pinch 2F Rotate 3F Flick 3F Flick 3F Press 2F ScrollZoomLR UD ZoomLR UD CorrectNo responseIncorrectCorrect No response Incorrect 15 16. Accuracy Results, Competitive StudyCorrect Gesture Recognition Rates120 100 80 Correct (%) System A 60System B System C40 209810097 62 77 68 9286 9397 97 1000Pinch Rotate FlickThree-Finger Press16 17. Satisfaction Questionnaire17 18. Satisfaction Questionnaire18 19. Questionnaire ResultI would use this gesture if it were available(strongly disagree = 1, strongly agree = 9) Pinch7.38Rotate4.383F 7.88Flick3F8.75 Press2F 8.25 Scroll 12345 6 789StronglyStronglyDisagree Agree19 20. Questionnaire, Competitive Rating FormatHow well do the gestures work on each system? Please rate from 1 (Poor) to 5 (Excellent) Gesture System A System B System C Pinch Zoom Rotate N/A Flick Left-Right Flick Up-DownN/A Three-Finger Press N/A N/A Two-Finger Scrolling20 21. Ratings ResultsUser Ratings With 95% Confidence Intervals Excellent 5432 Poor 1 Pinch Zoom 2F Rotate1F Rotate Flick LR Flick UD1F Scroll 1F Scroll2F Scrolling(Chiral)(Linear)(Circular)System A System B System C 21 22. Related Tests &amp; Gesture Side-EffectsOther usability tests for notebook input devices Pointing (target acquisition) Drag and drop Scrolling Typing and accidental TouchPad input Assess gesture side-effects Unintended gestures Other issues22 23. Conclusions Properties of gestures call for careful testing Gesture introduction and documentation is key Gestures are nondeterministic less predictable Gestures are interdependent; test as a set Framework of gesture tests 1. Gesture Introduction 2. Familiarity and Practice Tasks 3. Accuracy Tasks 4. Satisfaction Questionnaire and Debrief 5. Related Tests &amp; Gesture Side-Effects 23 24. Resources References Sylvia Le Hong and Dan Mauney, Cultural Differences and Similarities in the Use of Gestures on Touchscreen User Interfaces, UPA 2010.blog.humancentric.com/gesture-research/ Mark Billinghurst and Bill Buxton, Gesture Based Interaction in Human Input to Computer Systems (draft), www.billbuxton.com/inputManuscript.html Dan Saffer, Designing Gestural Interfaces, OReilly 2008. Craig Villamor, Dan Willis, Luke Wroblewski, Touch Gesture Reference Guide, www.lukew.com/touch/ Jacob Wobbrock , Meredith Ringel Morris, Andrew Wilson, User- Defined Gestures for Surface Computing, CHI 2009. Mike Wu, Chia Shen, Kathy Ryall, Clifton Forlines, Ravin Balakrishnan, Gesture Registration, Relaxation, and Reuse for Multi-Point Direct- Touch Surfaces, IEEE Tabletop 2006. Contact karthur@synaptics.com, touchusability.com Acknowledgments Usability colleagues at Dell, HP, Lenovo, Synaptics 24 </p>