This case study examines the design of a new voice messaging user interface (UI C) to be compatible with both an existing UI (UI A) and standard guidelines. UI C was tested against UI A by having expert UI A users perform tasks to rate ease of use. UI C achieved ratings showing it was as easy to use as UI A for most tasks, including frequent tasks. While deviating from standards on some aspects, UI C aligned with them for 45% of aspects tested, and achieved the goal of being compatible with both the existing UI and standards. The study shows subjective user testing is important and that an overall positive assessment can result from mostly positive ratings of individual tasks.

1. Standards in Practice:Standards in Practice:
A Case Study of Voice MessagingA Case Study of Voice Messaging
John P. ChinJohn P. Chin

2. IntroductionIntroduction
Usability Goals and ObjectivesUsability Goals and Objectives
Design IssuesDesign Issues
UI StandardsUI Standards
ISO 13714ISO 13714
Voice Messaging User Interface ForumVoice Messaging User Interface Forum
(VMUIF)(VMUIF)
Usability Test ResultsUsability Test Results

3. Goals and ObjectivesGoals and Objectives
SituationSituation
Existing User Interface (UI) A incompatibleExisting User Interface (UI) A incompatible
with UI Bwith UI B
Customers object to replacing existing UI ACustomers object to replacing existing UI A
with UI Bwith UI B
SolutionSolution
Create third UI C that is more compatible withCreate third UI C that is more compatible with
UI AUI A
UI C to comply with standards as much asUI C to comply with standards as much as
possiblepossible

4. Listen MenuListen Menu
UI AUI A UI BUI B
11 22 33
44 55 66
77 88 99
** 00 ##
RewindRewind PausePause Fast ForwardFast Forward
HelpHelpCancelCancel
EraseErase ReplyReply SaveSave
Envelope InfoEnvelope Info
11 22 33
44 55 66
77 88 99
** 00 ##
Reply/ForwardReply/Forward PausePause DeleteDelete
PlayPlay
ControlControl
Access MenuAccess Menu
SofterSofter SlowerSlower FasterFaster
RewindRewind
SkipSkip
RepeatRepeat LouderLouder Fast ForwardFast Forward
SkipSkip
ForwardForward

5. AssessmentAssessment
UserUser
Interface BInterface B
UserUser
Interface AInterface A
11%11%

6. Listen MenuListen Menu
ISO 13714ISO 13714 VMUIFVMUIF
11 22 33
44 55 66
77 88 99
** 00 ##
RepeatRepeat SaveSave DeleteDelete
HelpHelp
Backup orBackup or
CancelCancel
RewindRewind ResumeResume Fast ForwardFast Forward
SkipSkip
ReplyReply
PausePause
11 22 33
44 55 66
77 88 99
** 00 ##
PlayPlay SaveSave DeleteDelete
ControlControl
Access MenuAccess Menu
RewindRewind Fast ForwardFast Forward
SkipSkip

7. Listen MenuListen Menu
UI AUI A
ISO 13714ISO 13714
11 22 33
44 55 66
77 88 99
** 00 ##
RewindRewind PausePause Fast ForwardFast Forward
HelpHelp
EraseErase ReplyReply SaveSave
Envelope InfoEnvelope Info
SkipSkip
RepeatRepeat ForwardForward
Backup orBackup or
CancelCancel
11 22 33
44 55 66
77 88 99
** 00 ##
PlayPlay SaveSave DeleteDelete
ControlControl
Access MenuAccess Menu
RewindRewind Fast ForwardFast Forward
SkipSkip

8. AssessmentAssessment
UserUser
Interface BInterface B
UserUser
Interface AInterface A
11%11%
ISO 13714ISO 1371453%53% 46%46%

9. Listen MenuListen Menu
UI AUI A UI CUI C
11 22 33
44 55 66
77 88 99
** 00 ##
RewindRewind PausePause Fast ForwardFast Forward
HelpHelp
EraseErase ReplyReply SaveSave
Envelope InfoEnvelope Info
11 22 33
44 55 66
77 88 99
** 00 ##
RewindRewind PausePause Fast ForwardFast Forward
HelpHelp
Backup orBackup or
CancelCancel
DeleteDelete Reply/ForwardReply/Forward SaveSave
Envelope InfoEnvelope Info
SkipSkip
RepeatRepeat RepeatRepeat
SkipSkip
ForwardForward
Backup orBackup or
CancelCancel

10. AssessmentAssessment
UserUser
Interface BInterface B
UserUser
Interface AInterface A
11%11%
61%61% 15%15%
User Interface CUser Interface C

11. AssessmentAssessment
UserUser
Interface BInterface B
UserUser
Interface AInterface A
11%11%
61%61% 15%15%
User Interface CUser Interface C
ISO 13714ISO 13714
53%53% 46%46%
VMUIFVMUIF
45%45%
37%37%

12. MethodMethod
Nine expert users of UI A rated ease of use ofNine expert users of UI A rated ease of use of
UI CUI C
Performed 17 different tasks forPerformed 17 different tasks for
Administration, Get Messages, SendAdministration, Get Messages, Send
MessagesMessages
Rated tasks and overall systemRated tasks and overall system
Scale:1 = Extremely difficult to 7 = ExtremelyScale:1 = Extremely difficult to 7 = Extremely
easyeasy
Wrote additional comments whenWrote additional comments when
appropriateappropriate

13. ResultsResults
UI C was rated neither harder or easier than UIUI C was rated neither harder or easier than UI
AA
Rate task moderate (6) or extremely easy (7)Rate task moderate (6) or extremely easy (7)
85% rate frequent and critical tasks85% rate frequent and critical tasks
Save, Erase and SkipSave, Erase and Skip
80% rate typical features80% rate typical features
Overall, 77% of the goals were achievedOverall, 77% of the goals were achieved

14. Lessons LearnedLessons Learned
Subjective measures are an importantSubjective measures are an important
considerationconsideration
Deviate from standards to avoid destructiveDeviate from standards to avoid destructive
actionsactions
Users won’t over generalize negative ratingsUsers won’t over generalize negative ratings
Ratings will vary from one task to anotherRatings will vary from one task to another
Overall assessment of the UI will reflect theOverall assessment of the UI will reflect the
majority of the ratings.majority of the ratings.