Default Value: 0.5
The speech recognition confidence level, a float value in the range of 0.0 to 1.0. Results are rejected (a nomatch event is thrown) when application.lastresult$.confidence is below this threshold. The platform has been finely tuned to minimize the number of false positives above 0.5, and as such lowering this value is not recommended.
<?xml version="1.0"?><vxml version="2.0"><property name="confidencelevel" value="0.75"/><form><field type="boolean"><prompt>Please say yes or no.</prompt></field></form></vxml>
From this example, the threshold of the confidence level is raised to 0.75, requiring a clear response of a “yes” or “no” answer. Using a high confidence level setting is useful for when you are expecting a precise match to your grammar.