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How to tacle with common usability violations of VUI


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How to tacle with common usability violations of VUI (Voice User Interface), how to create IVR with high User Experience.

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How to tacle with common usability violations of VUI

  1. 1. How to tacle with common usability violations of VUI UX Camp Europe - Berlin , June 2011 Pavel Růžička (T-Mobile Czech Republic)
  2. 2. #1: Menu length <ul><li>Menu length determines how long you have to wait in order to hear all options explained with a prerecorded system message </li></ul><ul><li>Most callers who encounter long menus hang up in frustration, make mistakes in their choices, or try to connect to an operator </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Keep the greeting and preamble short (under five seconds) and present choices quickly. </li></ul></ul><ul><ul><li>Consider human short term memory (30 seconds) </li></ul></ul><ul><ul><li>Include only necessary legal disclaimers </li></ul></ul><ul><ul><li>Eliminate Marketing Messages </li></ul></ul>
  3. 3. #2: Number of menu choices <ul><li>In DMTF applications the caller must remember both the subject and the digit to select </li></ul><ul><li>As soon as the caller assumes that the current option within a list is the right option to choose, he/she will choose it (even if it‘s wrong) </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Four menu items are optimal </li></ul></ul><ul><ul><li>Arrange choices by popularity </li></ul></ul><ul><ul><li>Announce availability of details and allow users to choose it </li></ul></ul><ul><ul><li>Consider using verbs instead of nouns for menu items </li></ul></ul><ul><ul><ul><li>&quot;Administrate&quot; instead of &quot;Administration&quot; &quot;Check billing&quot; instead of &quot;Bill&quot; </li></ul></ul></ul>
  4. 4. #3: Operator access <ul><li>There is always battle between users who like talking to a real person and IVR‘s that have the goal to exactly avoid that </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Callers should know that they always have the option of speaking with a live agent : This will reduce frustration and increase user confidence </li></ul></ul><ul><ul><li>Don‘t try to hide access or make it conditional </li></ul></ul><ul><ul><li>Make it less attractive, e.g. by informing about longer waiting times </li></ul></ul><ul><ul><li>Think about rewarding users who try automation </li></ul></ul><ul><ul><li>Automate what’s useful – not what’s possible </li></ul></ul>
  5. 5. #4: Speech Intelligibility <ul><li>The understandability of the prompts, menus and instructions is crucial </li></ul><ul><li>Quite often there is a wrong use of prosody </li></ul><ul><ul><li>Prosody is a part of speech not associated with content, but with style of delivery </li></ul></ul><ul><li>What to do? </li></ul><ul><ul><li>Use friendly, plain pronunciation </li></ul></ul><ul><ul><li>Educate your voice talent to use appropriate voice modulation </li></ul></ul><ul><ul><li>Provide script details for the voice talent </li></ul></ul><ul><ul><li>Keep prompts short, but not fast </li></ul></ul><ul><ul><ul><li>verbs instead of nouns are better for the most languages/cultures </li></ul></ul></ul>
  6. 6. #5: Speech pacing <ul><li>Speech Pacing is the rhythm and speed of the recorded words callers hear </li></ul><ul><li>Non-professional speech talent tend to rush through scripts when they are recording prompts </li></ul><ul><li>Some designers think that the faster you speak, the faster you are serving the caller </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Generally, slow down the speed </li></ul></ul><ul><ul><li>Use appropriate pauses between words and sentences </li></ul></ul><ul><ul><li>Be aware that callers are not specialists </li></ul></ul>
  7. 7. #6: Forced output <ul><li>Forced output can‘t be interrupted by the user </li></ul><ul><li>This can be especially trouble for power users who know exactly what their preferred task sequence is </li></ul><ul><li>Many forced messages are the legal disclaimers and marketing messages </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Generally enable Barge-In </li></ul></ul><ul><ul><li>Inform the caller about possibility to interrupt </li></ul></ul><ul><ul><li>If you have to use forced messages, keep them short </li></ul></ul><ul><ul><li>Try to find way how to indicate to the user that barge-in event has been detected - even current media-platforms don 't support it </li></ul></ul><ul><ul><ul><li>immediatelly play an earcon or something like &quot;aha&quot; </li></ul></ul></ul>
  8. 8. #7: Task completion <ul><li>A tasks is a sequence of input steps to fulfill a request </li></ul><ul><li>The entire task is only as good as the worst input step </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Make use of navigational options – step back, cancel... </li></ul></ul><ul><ul><li>Analyze what step is the worst step – then improve it </li></ul></ul><ul><ul><li>Compare length of task using implicit vs. explicit confirmation steps </li></ul></ul><ul><ul><li>Use variations in wording during reprompting – dialog will also sound more natural </li></ul></ul>
  9. 9. #8: Error recovery <ul><li>Error recovery techniques are used to guide callers out of a known “bad state” and back into a “stable state”. </li></ul><ul><li>Errors can be caused by users (misunderstanding) or by systems (backend or misrecognition) </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Use silence or &quot;earcon&quot; as an indication for turn taking </li></ul></ul><ul><ul><li>You can provide &quot;try again&quot; option </li></ul></ul><ul><ul><li>Provide graceful degradation </li></ul></ul><ul><ul><li>Build touch-tone fallback into speech applications </li></ul></ul><ul><ul><li>Base d esign on the reality of errors - test driven development (TDD) </li></ul></ul><ul><ul><li>Don’t declare errors, ask to clarify input </li></ul></ul>
  10. 10. #9: Predictability <ul><li>Unpredictable behavior includes customer delay time and unexplained hang-ups or disconnections </li></ul><ul><li>Customer delay time is the total amount of time a caller is waiting to complete a task when nothing of value is happening </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Once you think everything is okay, you are in trouble </li></ul></ul><ul><ul><li>Track IT infrastructure downtime </li></ul></ul><ul><ul><li>Track call center anomalies and traffic </li></ul></ul><ul><ul><li>All of the backend systems must not shorter timeout than his underlying provider in hierarchy of components – or timeout event must be indicated </li></ul></ul><ul><ul><li>Consider asynchronous call of backend </li></ul></ul>
  11. 11. #10: Dead ends, unattended hang-ups <ul><li>Dead end are conditions that forces the caller to hang up and call back </li></ul><ul><li>Usability test subjects indicate a strong dislike of having to make repeated calls to get service </li></ul><ul><li>What to do? </li></ul><ul><ul><li>Test every path on a regular base </li></ul></ul><ul><ul><li>Audit the system periodically and test all numbers/words at every level of every menu </li></ul></ul><ul><ul><li>Build in caller-in-control features like go back , main menu and agent into your application . </li></ul></ul>
  12. 12. Summary: C ommon usability violations of VUI <ul><li>#1: Menu length </li></ul><ul><li>#2: Number of menu choices </li></ul><ul><li>#3: Operator access </li></ul><ul><li>#4: Speech Intelligibility </li></ul><ul><li>#5: Speech pacing </li></ul><ul><li>#6: Forced output </li></ul><ul><li>#7: Task completion </li></ul><ul><li>#8: Error recovery </li></ul><ul><li>#9: Predictability </li></ul><ul><li>#10: Endless loops </li></ul>
  13. 13. Resources <ul><li>Udo Glaeser , DTAG (presentation): VUI Best Practices - Athens, May 2011 </li></ul><ul><li>Larson-Tech: Ten Guidelines for Designing a Successful Voice User Interface </li></ul><ul><li>Voxeo : Interact Naturally With Your Callers </li></ul>
  14. 14. Pavel Růžička Programmer – Analyst Service Development Department T-Mobile Czech Republic a.s. Tomíčkova 2144/1, CZ 14900, Prague Phone: +420 603 416974 E-Mail: [email_address] Web: