The influence of pane position on CSCW * task performance in joint action perception space

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

*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)


Problem statement

What is better for a task that includes both communication and drawing; a horizontal oriented screen or a vertical oriented screen?

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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.


Research questions

• H0 = There will be no difference in the task performance between Setup 1 and Setup 2.


Experimental set up

VIP system and horizontal

set up Vertical set up, camera Remote station


Sample size

• Usable data: 10 subjects• Age 23-36• Experienced with drawing applications• Students from USI


Tasks

• Video-conference with experimenter

• Draw lines between basic geometrical figures

• Digital pen as drawing tool

• Within subjects design


Errors

Correct task execution

ErrorTask figure


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


Analysis

1010N =

1=hor, 2=vert

21

TIM

E

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20

7

• 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 outliersAn 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.


AnalysisRough scores

Dtime,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 ddev = 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 dtime = 0,75. The two distributions overlap (but still a big effect)


Analysis

Assume the conditions for the parametric test are met:T-test.


Analysis

• Communication errorsSignificantly more errors in the vertical condition than in the horizontal condition (p < .05).

• SatisfactionWhich setting do you prefer?Half of the participants preferred the horizontal setting;Two preferred the vertical;Three had no opinion.


Problems

• Preparing the vertical set up • Calibration of the pen

• Counterbalance

• Drawing figures


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.

The influence of pane position on CSCW * task performance in joint action perception space

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