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TAUCHI – Tampere Unit for Computer-Human Interaction

Manual Text Entry: Experiments,
Models, and Systems
Poika Isokoski
Tampere Unit for Computer-Human
Interaction
Department of Computer Sciences
University of Tampere, Finland

TAUCHI – Tampere Unit for Computer-Human Interaction

Writing

• There is no natural way to write.

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TAUCHI – Tampere Unit for Computer-Human Interaction

At School

• I did not understand why the inferior
pen and paper technology was still
taught to children.

2

TAUCHI – Tampere Unit for Computer-Human Interaction

Multiple writing technologies

• Pen and paper and computers are
used for writing.

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TAUCHI – Tampere Unit for Computer-Human Interaction

Structure of the Work
II: Comparison of two Toucpad-Based

I: Device Independent Text Input:
Rationale and an Example

Methods for Numeric Entry

III: Evaluation of Multi-device
Extension of Quikwriting

IV: Performance of Menu-augmented
Soft Keyboards

V: Model for Unistroke writing time
VI: Combined Model for
Text Entry Rate Development

VII: Architecture for Personal
Text Entry Methods
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TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Introduction
• Performance of Menu-Augmented Soft
Keyboards
• Video

5

TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Model
• Simulator:
– Fitts’ law for pointing ( t = a + b
log(A/W+1) ).
– Constant 160 ms for selection (McQueen et
al., GI 1995).
– Given a text string the simulator computes
how long entering it takes.

• Used the 500 phrase set published by

MacKenzie and Soukoreff (CHI2003).
• demo
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TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Model: results

Words per minute

60
50
40
30
20
10
0
Dvorak

QWERTY

OPTI II

No menu

• QWERTY: 26% faster
7

ATOMIK

Menu

FITALY

TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Model: discussion 1
• Why does it seem to be faster?
• Because it saves stylus travel:
– Without menu:

– With menu:

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TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Model: discussion 2
• Is the model realistic and reliable?
– Maybe.
– It could reflect user’s motor performance
fairly accurately.
– It does not know anything about cognitive
factors.

 Experiments are needed.
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TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Experiment I: task
• Measured the motor performance.
– 12 participants entered repeating patterns:

1

TAUCHI – Tampere Unit for Computer-Human Interaction

700
600

• When the patterns are simple (left),
using the menu is faster
• When the patterns are more complex
menu
menu
(right), the difference
isnosmaller

500

400
300
200
100

1

pälä

p_l_

polo

pili

pulu

pyly

pele

pala

pl

päl

p_l

pil

pol

pattern

pul

pyl

pel

pal

no

ko

mi

lo

pä

p_

po

pi

pu

py

pe

pa

0
pp

time per character (ms)

Paper IV: Experiment I: results

TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Experiment I: discussion
• Atomic menu selection is faster than
pointing (on average).
• Deciding whether to point or select
takes time.
• It could be that in real writing situation
the cognitive planning dominates
making using the menu slower than
not using it.
 Another experiment was needed.
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TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Experiment II: task
• Text transcription task:
– The same software
– 6 participants
– 20 sessions (15 min with the menu and 15
min without it per session)
– The menu was optimized based
on the results of Experiment I

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TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Experiment II: results
• Text entry rate:
text entry rate (wpm)

35

y = 17.833x 0.1166
R2 = 0.9837

30
25
20
15

y = 9.8911x 0.314
R2 = 0.9968

10

menu
no menu

5
0
0

10

session

20

30
1

TAUCHI – Tampere Unit for Computer-Human Interaction

Paper IV: Conclusions
• Using the menu may allow faster text
entry rates, but
– only after a lot of training (>>5 hours)
– at the cost of added cognitive load
– the increase in text entry rate may not be
that great (model says max 26%).

• The menu does not disturb those users
who do not want to use it.

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TAUCHI – Tampere Unit for Computer-Human Interaction

Summary

• The thesis contributes in four ways:
–
–
–
–

Device independent text entry
Data on text entry method performance
Models of user performance
A software architecture for text entry

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