User Perceptions of Drawing Logic Diagrams with Pen-Centric User Interfaces Bo Kang, Jared N. Bott, and Joseph J. LaViola Jr. Interactive Systems & User Experience Lab Department of EECS University of Central Florida

Outline Related Work Motivation Experiment Results Discussion Conclusion

Related Work Pen-based Interfaces –DENIM (Lin et al. 2000) –CrossY (Apitz et al. 2004) –LogicPad (Kang and LaViola 2012) Evaluation and Perceptions –MacKenzie et al. (1991) –Wais et al. (2007) –Forsberg et al. (2008) –Vatavu et al. (2011) –Bott et al. (2011)

Motivation LogicPad –Hybrid interface for Boolean logic problems –Seemed faster than sketching Is speed more important for these diagrams?

Experiment Performed study comparing 3 pen-based interfaces for creating Boolean logic diagrams

Sketch Pure sketch, 100% accurate, “ideal”

Drag-and-Drop Traditional WIMP-based, stylus and keyboard

Hybrid Radial menu for gates, sketch labels and wires

Subjects and Apparatus 18 college students participated –3 female, 15 male –Ages 19 – 30 Worked on tablet PC –HP EliteBook 2760p

Experimental Task 3 copy-and-verify tasks (one per interface) –6 problems per task Given a diagram- equation pair Copy a diagram using interface, get a Boolean equation back Compare given equation with one from interface

Experimental Design Wizard of Oz approach –All 3 interfaces programmed with ordering of tasks, which equation to show 3 by 2 within-subjects factorial design –Independent variables: user interface (sketch, drag-and-drop, hybrid) and diagram complexity (low, high) –Dependent variable: completion time

Metrics Measured completion time Rate each interface –Making gates –Making wires –Making labels –Arrange gates –Create diagrams –Speed –Frustration Rank interfaces –Ease of use –Speed –Naturalness –Overall preference

Hypotheses Primary: Participants will prefer the sketch interface over the hybrid and drag-and- drop interfaces Secondary –Hybrid interface will be faster than the sketch and drag-and-drop interfaces –Sketch interface will be rated more natural than the hybrid and drag-and-drop interfaces

Results - Rankings

Results – Completion Time InterfaceDrag-and-DropHybridSketch Complexityσσσ Low High Overall T-tests on completion time –Sketch faster than drag-and-drop –Hybrid faster than drag-and-drop –Hybrid faster than sketch, except at low complexity (no significance)

Results – Ratings Significant tests –Ease of use in labeling, arranging, and creating diagrams Easy label: sketch > hybrid > drag-and- drop Easy arrange: drag-and-drop > sketch Easy diagram: hybrid > drag-and-drop

Results – Hypotheses Primary hypothesis – Did they prefer sketch interface? –No Was sketch most natural? –Yes Was hybrid fastest? –Yes…

Discussion Speed and user perceptions –Difference in rankings/ratings and completion time –Why? No task switching with sketch interface Internal versus external mistakes Drawing style slows down sketching –No easy way to spatial arrange drawing –100% sketch accuracy not as fast as hybrid

Discussion – cont. Why rank an interface as best overall? –Spearman’s rank correlation between overall ranking and other rankings and ratings –Highest correlations with ease of use ranking, naturalness ranking, speed ranking –Sketch “was fast for small diagrams” –Sketch “was easy and natural” –Hybrid “easier than the others”

Conclusion Would users prefer a sketch interface over a faster interface? –Study comparing three pen-based interfaces for creating logic diagrams –Sketch was well-liked, but not decisively so User perceptions and measurements –Perception of speed and our measurement differed Should we continue research into pen-based interfaces for structured 2D languages? –Yes Pure sketch might not be the most powerful, but clearly desirable traits

Acknowledgments This work is supported in part by NSF CAREER award IIS and NSF awards IIS and CCF

QUESTIONS? Bo Kang: Jared N. Bott: Joseph J. LaViola Jr.:

Ratings InterfaceDrag-and-dropSketchHybrid Statementσσσ Easy gate Easy wire Easy label Easy arrange Easy diagram Quick Frustrating

Correlations Correlation with Overall Ranking ρ p Ease of Use Naturalness Speed Frustration Easy Diagram Easy Label Completion Time Quick Easy Gate Easy Wire Easy Arrange