The voice stress technology operates on the principal that the human voice has two frequencies. When a person is under high stress or lying the frequencies change and that causes micro tremors in the voice. The voice stress instrument detects the changes or lack of changes and displays them on a chart to be analyzed by the examiner. There are several types of voice analyzers on the market. Some of the analyzers use computers to display the frequencies and aid in the analysis.

The plus with voice stress analysis is that the persons being tested does not need to be present. With this type of analysis the accuracy will be less. Analysis of a persons voice without their knowledge brings up many legal issues and is not recommended.

Which is more accurte the polygraph or voice stress evaluator? The answer is who are you asking. Polygraph examiners will say they are more accurate. Voice stress will say that they are more accurate. The polygraph measures five areas for evaluation and the voice stress measures one. With this, a person would think that the polygraph would be more accurate than the voice stress evaluation. This is a very complex issue and the space provided here can not afford the room to bring out and discuss all the issues on this topic.

In 1989 the Federal Government passed the Polygraph Protection Act. Pre-employment polygraph testing is now limited to federal and local government agencies, armored car services, those dispensing controlled substances and security companies involved in national security.

Employee Theft and Misconduct

Prove that there is an ongoing investigation in regards to the incident.

Prove that the person to be tested had more than "just access" to the items missing or the incident under investigation. This can be from information received from an anonymous source. This can also be another employee witness an unusual transaction may by the employee in question.

Advise the employee of their rights under the polygraph protection act.

The employee must be given a form showing the purpose of the test and why they are being ask to take a test. If they refuse the employer can not take any adverse action against the employee.

There is a 48 hour waiting period after the employee receives the form. After the 48 hour waiting period the test can be given, if the employee agrees to do so. This does not include weekends and holidays.

They must be given a form showing the date, time and location of the test.

These are non-waivable rights. This means that an employee can not waive their rights under this act.

The results of the test can not be used to take any adverse action against the employee.

If deception is indicated, then the employee must be given a copy of the polygraph examiners report.

The polygraph examination must be at least ninety minutes in duration. The examiner must produce at least two polygraph charts during the examination.