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chapter_-_9_modality [2019/06/05 11:16]
crispin_reedy_yahoo.com 		chapter_-_9_modality [2019/08/08 13:38] (current)
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 **// Switching //**\\ **// Switching //**\\
-After repeated speech errors, some systems will switch the rest of the call to DTMF. This takes some upfront planning and work to implement the dialog steps in both speech and DTMF, but, as described in more detail below in the section on Error Recovery, allows callers to continue self-routing and self-service when speech doesn'​t work well. This strategy can keep callers in the system who would otherwise get transferred to a customer service representative,​ whether or not the caller wanted to transfer. In making the decision about what to do when speech fails, companies need to balance their relative costs and benefits of providing a touchtone fallback versus faster transfer to agents. "For example, enterprises that face significant competition and with customers who can easily change providers might choose a strategy of rapid transfer over touchtone fallback"​ (Lewis, 2011, p. 186).+After repeated speech errors, some systems will switch the rest of the call to DTMF. This takes some upfront planning and work to implement the dialog steps in both speech and DTMF, but, as described in more detail below in the section on Error Recovery, allows callers to continue self-routing and self-service when speech doesn'​t work well. This strategy can keep callers in the system who would otherwise get transferred to a customer service representative,​ whether or not the caller wanted to transfer. In making the decision about what to do when speech fails, companies need to balance their relative costs and benefits of providing a touchtone fallback versus faster transfer to agents. "For example, enterprises that face significant competition and with customers who can easily change providers might choose a strategy of rapid transfer over touchtone fallback"​ ([[references#​lewis2011|Lewis, 2011]], p. 186).
  
 **// Promote Where Appropriate //**\\ **// Promote Where Appropriate //**\\
-Provide a touchtone alternative for tasks that are easier for DTMF than speech. The best example of this is the entry of numeric strings, such as PIN codes, account numbers, social security numbers, etc. These types of prompts usually start with the phrase "Say or enter ...," which is a concise way to let callers know they have a choice (and one with which callers tend to be familiar). Analyses of actual usage of these types of prompts shows that most callers choose to use the keypad (60% reported by Suhm, 2008; 90% reported by Attwater, 2008).+Provide a touchtone alternative for tasks that are easier for DTMF than speech. The best example of this is the entry of numeric strings, such as PIN codes, account numbers, social security numbers, etc. These types of prompts usually start with the phrase "Say or enter ...," which is a concise way to let callers know they have a choice (and one with which callers tend to be familiar). Analyses of actual usage of these types of prompts shows that most callers choose to use the keypad (60% reported by [[references#​suhm2008|Suhm, 2008]]; 90% reported by [[references#​attwater|Attwater, 2008]]).
  
 Another approach is to use mode-neutral prompts such as, "Next, what's your PIN?" Ideally, the application should accept either speech or DTMF for this prompt. This is not as effective as "say or enter,"​ especially if it follows several speech prompts. Callers may not realize that they can use DTMF. Another approach is to use mode-neutral prompts such as, "Next, what's your PIN?" Ideally, the application should accept either speech or DTMF for this prompt. This is not as effective as "say or enter,"​ especially if it follows several speech prompts. Callers may not realize that they can use DTMF.
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 It’s always a good idea to allow users to fall back to DTMF input in cases where users are experiencing multiple errors with speech. No matter how robust a system’s grammars are, there will be times when the user’s environment - barking dog, loud television, competing voices - will make speech recognition extremely challenging. If possible, consider turning off the recognizer and switching to a DTMF-only mode if the system reaches a predetermined No Match threshold. It’s always a good idea to allow users to fall back to DTMF input in cases where users are experiencing multiple errors with speech. No matter how robust a system’s grammars are, there will be times when the user’s environment - barking dog, loud television, competing voices - will make speech recognition extremely challenging. If possible, consider turning off the recognizer and switching to a DTMF-only mode if the system reaches a predetermined No Match threshold.
  
-When callers have difficulty with a speech recognition IVR, it is a common practice to allow callers to use DTMF (the touchtone keypad) as an alternative input mechanism (Balentine, 2010; Rolandi, 2004a; Suhm, 2008). Callers might have problems using speech for reasons such as:+When callers have difficulty with a speech recognition IVR, it is a common practice to allow callers to use DTMF (the touchtone keypad) as an alternative input mechanism ([[references#​balentine2010|Balentine, 2010]]; [[references#​rolandi2004a|Rolandi, 2004a]]; [[references#​suhm2008|Suhm, 2008]]). Callers might have problems using speech for reasons such as:
     * Caller accent ​     * Caller accent ​
     * Speech disability     * Speech disability
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 If the primary problem is ambient noise, then it may be necessary to disable speech to prevent the system speech from cutting off before the caller hears the prompts/​messages. If the primary problem is ambient noise, then it may be necessary to disable speech to prevent the system speech from cutting off before the caller hears the prompts/​messages.
  
-Research continues in making speech recognition more robust in the face of ambient noise, but this is still a significant problem for current technologies (Karray & Martin, 2003), just as it is for human-human dialogs (McKellin et al., 2007).+Research continues in making speech recognition more robust in the face of ambient noise, but this is still a significant problem for current technologies ([[references#​karray|Karray & Martin, 2003]]), just as it is for human-human dialogs ([[references#​mckellin|McKellin et al., 2007]]).
  
-"​Because disabling speech barge-in can cause significant usability problems with speech input, it is better to disable speech input altogether and to stay in touchtone mode following multiple speech failures [in the condition of high ambient noise], still permitting touchtone barge-in"​ (Lewis, 2011, p. 186).+"​Because disabling speech barge-in can cause significant usability problems with speech input, it is better to disable speech input altogether and to stay in touchtone mode following multiple speech failures [in the condition of high ambient noise], still permitting touchtone barge-in"​ ([[references#​lewis2011|Lewis, 2011]], p. 186).
  
 If disabling speech and switching to DTMF-only for the rest of the session, consider playing a concise prompt such as, "​Let'​s use the keypad from here on." If disabling speech and switching to DTMF-only for the rest of the session, consider playing a concise prompt such as, "​Let'​s use the keypad from here on."
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 Avoid using prompts like, "For checking, press or say 1. For savings, press or say 2. For money market, press or say 3." Avoid using prompts like, "For checking, press or say 1. For savings, press or say 2. For money market, press or say 3."
  
-This is a common (but far from leading) practice. Lewis (2007) searched the Web and found numerous examples of applications using this prompting style, but no examples of designers promoting it. This type of prompting inherits the weaknesses of DTMF-only applications (needing to remember a number instead of the desired function) and speech applications (possibility of misrecognition),​ without getting any of the advantages of well-designed speech applications. Designers have argued against this practice for over ten years:+This is a common (but far from leading) practice. ​[[references#​lewis2007|Lewis]] (2007) searched the Web and found numerous examples of applications using this prompting style, but no examples of designers promoting it. This type of prompting inherits the weaknesses of DTMF-only applications (needing to remember a number instead of the desired function) and speech applications (possibility of misrecognition),​ without getting any of the advantages of well-designed speech applications. Designers have argued against this practice for over ten years:
  
-"​Asking the user to speak a digit for menu selections or other non-numeric data -- simply to emulate the touch-tone keypad -- is extremely awkward. Although speech recognition technologies of several years ago were limited to such vocabularies,​ this is no longer the case" (Balentine & Morgan, 2001).+"​Asking the user to speak a digit for menu selections or other non-numeric data -- simply to emulate the touch-tone keypad -- is extremely awkward. Although speech recognition technologies of several years ago were limited to such vocabularies,​ this is no longer the case" ([[references#​balentine2001|Balentine & Morgan, 2001]]).
  
 **// Specify Modality in Prompts //**\\ **// Specify Modality in Prompts //**\\
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 There are times when you want to create a pure DTMF (touchtone) application. There are many reasons for this: an international caller base where even if everybody knows the same language, it's not their first language; an application targeted to an environment that is known to be noisy; a simple task or menu where speech doesn'​t buy you anything; or the Powers That Be decreed it so. There are times when you want to create a pure DTMF (touchtone) application. There are many reasons for this: an international caller base where even if everybody knows the same language, it's not their first language; an application targeted to an environment that is known to be noisy; a simple task or menu where speech doesn'​t buy you anything; or the Powers That Be decreed it so.
  
-Whatever the reason, most design principles carry over, but there are a few differences. Most significantly,​ with touchtone applications,​ you as a designer only have the phone keypad to work with, which limits interaction to selection from a menu or numeric input. It is possible to devise schemes for entering text, but these methods tend to be difficult to use because it's necessary to either disambiguate which letter a caller intends for each entered character (e.g., using multikey or multitap -- see Lewis et al., 1997, pp. 1292-1293 or Lewis et al., 2008, p. 113) or to disambiguate the entered string with some sort of database look-up. This places significant limitations on the kinds of tasks that callers can perform with a DTMF-only application.+Whatever the reason, most design principles carry over, but there are a few differences. Most significantly,​ with touchtone applications,​ you as a designer only have the phone keypad to work with, which limits interaction to selection from a menu or numeric input. It is possible to devise schemes for entering text, but these methods tend to be difficult to use because it's necessary to either disambiguate which letter a caller intends for each entered character (e.g., using multikey or multitap -- see [[references#​lewis1997|Lewis et al., 1997]], pp. 1292-1293 or [[references#​lewisc2008|Lewis et al., 2008]], p. 113) or to disambiguate the entered string with some sort of database look-up. This places significant limitations on the kinds of tasks that callers can perform with a DTMF-only application.
  
 If a broad menu goes beyond 9 items, necessitating double digits, it is better to split the menu into two menus. This will lead to a cleaner design and eliminate the risk of callers accidentally going down the wrong logic leg of a call flow due to any substantial latency between the first and second digits. If a broad menu goes beyond 9 items, necessitating double digits, it is better to split the menu into two menus. This will lead to a cleaner design and eliminate the risk of callers accidentally going down the wrong logic leg of a call flow due to any substantial latency between the first and second digits.