1.
Laboratory of Human-Computer Iinteraction
for Special Needs
J. Eduardo Pérez, Xabier Valencia, Myriam Arrue and Julio Abascal
University of the Basque Country (UPV/EHU)
A Usability Evaluation of Two Virtual Aids
to Enhance Cursor Accessibility
for People with Motor Impairments
:
www.jeduardoperez.info
:
@j_eduardoperez
:
juaneduardo.perez@ehu.eus
April 12th 2016, Montreal (Canada)
Session 5: Non-Visual Access & Web Accessibility
The 13th Web for All Conference (W4A 2016)

2.
W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Motivation
• Point & click fundamental actions for Web browsing
> but challenging for dexterity impaired [Trewin, 2008]
Trewin, S. and Pain, H. (1999) Keyboard and mouse errors
due to motor disabilities. IJHCS 50(2), 109-144.
Hwang, F., Keates, S., Langdon, P. and Clarkson, P.J. (2004) Mouse movements
of motion-impaired users: a submovement analysis. ASSETS ’04, 102-109.
Pérez, J. E., Arrue, M., Valencia, X. and Moreno, L. (2014) Exploratory study of web
navigation strategies for users with physical disabilities. W4A ’14, article 20.
• Motion-impaired face problems when using standard input devices [Trewin, 1999]
Have difficulties selecting targets on GUIs [Hwang, 2004]
• Similar difficulties for point & click using AT (keyboard, joystick and trackball)
Heterogeneous behaviours depending on AT group [Pérez, 2014]
– Joystick & trackball users è less accurate pointing
– keyboard users è more affected by target distance
Trewin, S. (2008) Physical Impairment. Web Accessibility:
A Foundation for Research (Springer), 37-46.
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W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
• Two cursor virtual aids developed for web browsing assistance
(based on assistive technology used to access the Web [Pérez, 2014])
Cursor Aids
- to assist lack of dexterity
Pérez, J. E., Arrue, M., Valencia, X. and Moreno, L. (2014) Exploratory study of web
navigation strategies for users with physical disabilities. W4A ’14, article 20.
– CIRCULAR Cursor:
reduce accuracy required for clicking
– CROSS Cursor:
reduce target distance for pointing
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W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
• 3 cursor variants:
– circular, cross & unassisted
• 2 websites used as stimuli:
– informational [discapnet.com] & institutional [gipuzkoa.eus]
• 2 kind of tasks:
– 4 searching tasks [2x2x3] & 48 target acquisition tasks [24x2x3] with each cursor variant
• 8 categories to rate each cursor variant (7 points Likert scale):
– learnable, rememberable, accurate, easy to use, effortless, natural, fun, and not frustrating
• Rank cursor variants to conclude experiment:
– overall preferred option for Web browsing & for each of 8 categories
Experiment
- Outline
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W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Experiment
- Participants
• 15 subjects:
– 9 motion-impaired & 6 able-bodied
• 3 groups (based on pointing device used):
– 4 keyboard users [KU]
– 4 joystick & 1 trackball users [JU]
– 6 mouse users [MU]
• Expert users with pointing device:
– years of experience & continuous use
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W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Results
- Learnable & Rememberable
① “Rate how EASY TO LEARN to use the cursor variant was”
(1- very negative, 7- very positive)
§ Circular cursor highly rated by every user group.
§ Cross Cursor low results from JU and MU groups;
but highly rated by keyboard users.
② “Rate how EASY TO REMEMBER to use the cursor variant was”
(1- very negative, 7- very positive)
§ Unassisted cursor obtained best results – expected.
§ Circular cursor & Cross cursor also highly rated
by all groups.
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W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Results
- Accurate & Easy to Use
③ “Rate how ACCURATE the cursor variant was”
(1- very negative, 7- very positive)
§ Circular cursor highest ratings by motor-impaired
(3 able-bodied also show preference).
§ Cross cursor specially highly rated by KU group.
§ Unassisted cursor negatively rated by several motor-impaired.
④ “Rate how EASY TO USE the cursor variant was”
(1- very negative, 7- very positive)
§ Circular cursor best rated by motor-impaired.
§ Cross cursor last ranking for JU and MU groups,
but first choice for 50% of keyboard users.
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W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Results
- Effortless & Natural
⑥ “Rate how NATURAL to use the cursor variant was”
(1- very negative, 7- very positive)
§ Unassisted cursor highly rated by 3 groups.
§ Cross cursor last ranking for JU and MU groups,
but second choice for 50% of keyboard users.
⑤ “Rate how EFFORTLESS the cursor variant was”
(1- very negative, 7- very positive)
§ Circular cursor preferred for joystick & trackball users
(also very positively rated by mouse users).
§ Cross cursor preferred for keyboard users.
§ Unassisted cursor only preferred for mouse users.
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W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Results
- Fun & Not Frustrating
⑦ “Rate how FUN to use the cursor variant was”
(1- very negative, 7- very positive)
§ Similar mean values for variants and user groups.
§ Circular cursor highest ratings for the 3 user groups.
⑧ “Rate how NOT FRUSTRATING to use the cursor variant was”
(1- very negative, 7- very positive)
§ Both cursor enhancements very positively rated by each
aimed group (Circular cursor by JU group
& Cross cursor by KU group)
§ Circular & unassisted similar high rates from MU group.
§ Unassisted cursor most frustrating for 75% of KU group
& Cross cursor for 100% JU group.
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10.
• Motor-impaired participants mainly preferred one
of the two cursor variants proposed (7 out of 9) to
the unassisted cursor for Web browsing:
50% KU users è Cross cursor 1st
80% JU users è Circular cursor 1st
W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Results
- Overall Ranking
• Opposing assessments depending on pointing
device user group (KU vs. JU):
100% JU è Cross cursor 3rd
25% KU è Circular cursor 1st
50% KU è Circular cursor 2nd
25% KU è Circular cursor 3rd
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11.
W4A 2016A usability evaluation of two virtual aids to enhance cursor accessibility for people with motor impairments
Laboratory of Human-Computer
Iinteraction for Special Needs
Conclusions
ü Usefulness & acceptance of both virtual aids by participants with lack of dexterity
(Circular cursor / Cross cursor – depending on pointing device)
ü Importance of providing virtual aids for improving Web browsing to motor-impaired
q Analyse additional users interaction data gathered along experiments
è study different performance indicators for each cursor variant
Future
Work
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12.
Laboratory of Human-Computer Iinteraction
for Special Needs
Thank you for your attention
Questions?
A Usability Evaluation of Two Virtual Aids
to Enhance Cursor Accessibility
for People with Motor Impairments
:
www.jeduardoperez.info
:
@j_eduardoperez
:
juaneduardo.perez@ehu.eus
April 12th 2016, Montreal (Canada)
Session 5: Non-Visual Access & Web Accessibility
The 13th Web for All Conference (W4A 2016)