1. The influence of pane position on CSCW* task performance in joint action perception space *Computer Supported Collaborative Work G. Metaxas, B. Metin, E. Pelgrim, J. Schneider, G. Shapiro

2. *Computer Supported Collaborative Work VIP – USI ‘2004 Introduction Vertical screen more appropriate for communicating (social interaction; face-to- face communication) Horizontal screen more appropriate for working space (Meyer, Cohen & Nilsen, 1994; horizontal placement of input devices faster and favoured over vertical placement)

3. *Computer Supported Collaborative Work VIP – USI ‘2004 Problem statement What is better for a task that includes both communication and drawing; a horizontal oriented screen or a vertical oriented screen? [ ]

4. *Computer Supported Collaborative Work VIP – USI ‘2004 Objectives Main: To compare setting 1 with setting 2 based on the ISO standards (effectiveness, efficiency and satisfaction). Setting 1: Video-conferencing and drawing tool are both projected onto a horizontally placed digital board. Direct manipulation of the drawing tool by a digital pen. Setting 2: Video-conferencing tool and drawing tool are both presented on a vertical screen, digital pen is used to manipulate the drawing tool.

5. *Computer Supported Collaborative Work VIP – USI ‘2004 Research questions H0 = There will be no difference in the task performance between Setup 1 and Setup 2.

6. *Computer Supported Collaborative Work VIP – USI ‘2004 Experimental set up VIP system and horizontal set up Vertical set up, cameraRemote station

7. *Computer Supported Collaborative Work VIP – USI ‘2004 Sample size Usable data: 10 subjects Age 23-36 Experienced with drawing applications Students from USI

8. *Computer Supported Collaborative Work VIP – USI ‘2004 Tasks Video-conference with experimenter Draw lines between basic geometrical figures Digital pen as drawing tool Within subjects design

9. *Computer Supported Collaborative Work VIP – USI ‘2004 Errors Correct task execution ErrorTask figure

10. *Computer Supported Collaborative Work VIP – USI ‘2004 Measurements Dependent variables Efficiency: Time to complete a task Effectiveness: Total amount of errors during task Satisfaction: Ask directly which setting they prefer Independent variables Setting

11. *Computer Supported Collaborative Work VIP – USI ‘2004 Analysis T-test comparing the means of two related samples (the horizontal setting and the vertical setting). Wilcoxon Signed Ranks test comparing the medians of two related samples (more robust against extreme values). Check for outliers An outliers is an observation that has a value which is at least 1.5 * IQD above the third quartile or below the first quartile. p.s More individual variation in condition 2. Median: In condition 1, the horizontal condition, 50% of the participants performed the task in 70.3 or less seconds. Mean: 71.4 seconds.

12. *Computer Supported Collaborative Work VIP – USI ‘2004 Analysis Rough scores D time,gem. : On average all participants perform the task in the horizontal setting 33.8 seconds faster than in the vertical setting (rough effect) How big is this effect in proportion to the noise (individual variations)? Cohen’s d dev = 1,99, the error distributions of the two settings are very far apart from each other. All participants made more errors in the vertical condition than in the horizontal condition. Cohen’s d time = 0,75. The two distributions overlap (but still a big effect)

13. *Computer Supported Collaborative Work VIP – USI ‘2004 Analysis Assume the conditions for the parametric test are met: T-test.

14. *Computer Supported Collaborative Work VIP – USI ‘2004 Analysis Communication errors Significantly more errors in the vertical condition than in the horizontal condition (p <.05). Satisfaction Which setting do you prefer? Half of the participants preferred the horizontal setting; Two preferred the vertical; Three had no opinion.

15. *Computer Supported Collaborative Work VIP – USI ‘2004 Problems Preparing the vertical set up Calibration of the pen Counterbalance Drawing figures

16. *Computer Supported Collaborative Work VIP – USI ‘2004 Conclusion and Discussion Performance on different device orientations may depend on task (writing vs. drawing) Not sure if it can be generalized Participants perform better in the horizontal setting than in the vertical setting.  They are faster and make less errors. Participants make less communication errors in the horizontal setting. Participants prefer the horizontal setting.