# Confidence Thresholds

The system categorizes speech recognition with two confidence levels: low and high. Each utterance is analyzed and assigned a confidence value between 0.0 and 1.0, according to how well the system was able to match it with a word or name in its vocabulary.

When a confidence value meets or exceeds the "high" confidence level, the system recognizes the requested name, number, or department unambiguously and transfers the call to the appropriate destination.

When an utterance receives a confidence value below the "low" confidence level, the system does not recognize the requested name, number, or department and instructs the caller to repeat the call request.

When a confidence value falls between these levels, the system will seek explicit confirmation of its best match with the user before transferring the call.

The confidence thresholds can be adjusted using the configurable low/high confidence levels. The default values are appropriate for most installations. The following table outlines observed behavior and lists recommended actions:

Observation | Recommendation
--- | ---
Many calls result in confirmation requests with the expected name match. (Attendant says, "I heard <name>. Is that correct?") | Decreasing the high confidence level will allow more calls to be processed without explicit confirmation.
Many calls result in transfers to incorrect matches. | Increasing the high confidence level will ensure that more calls receive explicit confirmation before being transferred.
Many calls that are for valid names result in no match. (Attendant says, "I don't understand.") | Decreasing the low confidence level will allow more calls to be recognized, and receive explicit confirmation before being transferred.
Many calls result in confirmation requests with incorrect name matches. (Attendant says, "I heard <name>. Is that correct?") | Increasing the low confidence level will filter out more calls, requesting the caller to try again.

For confidence threshold configuration, refer to Basic Speech Recognition Parameters.

There are other adjustable parameters that affect speech recognition; we recommend that you leave these settings at their default values unless changes are requested by Mitel Product Support.