Barge-in: Part I

Barge-in -- the ability by the user to interrupt a system prompt with voice or DTMF input -- is a very useful tool that the VUI designer can tap into to effectively adapt to various exchange settings the system may need to navigate. The challenge for the VUI designer is determining when to give the user the ability to interrupt and when to take it away from them.

As a rule, you should let the user interrupt system prompts with their input, unless a good reason presents for taking that ability away from them. Three broad parameters need to be taken into consideration when considering turning off barge-in.

User's level of experience with the system

The first and perhaps most obvious factor the designer must consider when debating whether to turn barge-in on or off is the user’s level of experience and familiarity with the application. If the vast majority of users are going to be repeat users and therefore very familiar with the call flow and the options available at any point in the call (e.g., employee check-in/check out), then the default setting for barge-in should be “on”. If the user is going to be a one-time or very infrequent user (e.g., a phone survey), then the barge-in setting should default to “off”.

Call environment

If your application is called from noisy environments (e.g., busy street, factory floor), consider doing two things: first, set the value of your speech recognizer’s sensitivity below the default setting (this will enable the system to tolerate a higher threshold of noise without taking it as input from the user), and second, turn barge-in off, thus at least ensuring that the system will be able to complete playing the prompt to the user.

Conversational context

The third dimension the VUI designer must keep in mind to decide whether to turn barge-in on or off is the conversational context – i.e., where in the structure of the application is the call.

In the next couple of posts, I will list 6 guidelines as to when to turn barge-in on or off.