A computer voice stress analyzer (CVSA) is a truth verification system. A CVSA device consists of a microphone plugged into a computer, which is then used to analyze a person's response to a question. The computer will display a voice pattern as the person speaks. The voice pattern will be evaluated using a scoring system, which is interpreted by the examiner.
There are no known countermeasures to cause inconclusive results. An examiner must receive extensive training prior to being certified with a CVSA and must recertify every two years.