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When Should a Polygraph be Used?

  • December 28, 2006
  • by PInow Staff

Polygraph testing is used by many companies. Understanding where and when to use polygraphs is a must for any business looking for answers.

People lie all the time, and as law enforcement officials have known for a long time, when people lie, they often show it in some way. When being dishonest, some people avoid eye contact, others fidget, and others break into a sweat. Polygraph tests take this basic concept and create a measurable way of recording people's reactions to questions. A polygraph tests respiration, blood pressure, heart rate, and skin conductivity while the subject is being asked specific questions. By comparing the body's response to specific questions, polygraph examiners can verify the truthfulness of what a subject is saying.

Cases in which to use polygraph testing

There are a number of cases when polygraph testing is used:

  • For criminal and civil cases. In some cases related to civil lawsuits or criminal trials, hard evidence is not always available or not always enough.
    Polygraph testing is sometimes used to bolster evidence or to determine the trustworthiness of a witness. In many states, polygraph examiners are allowed to testify in criminal and civil cases. Police often use the polygraph in investigations across the country, but by law, no one can be forced to take the test. By law, refusal to take the test cannot affect a case's outcome.

  • For pre-employment screening. Government agencies hiring employees for sensitive jobs will often use polygraph screening to select candidates.

  • For issues related to homeland security. The Central Intelligence Agency, Federal Bureau of Investigation, National Security Agency, and other federal bodies charged with the nation's security routinely use polygraphs to uncover crimes and threats against the nation.

  • For commercial theft investigations. Businesses concerned about fraud and employee theft may be able to turn to the polygraph to gauge employee honesty and loyalty to the company.

  • For the monitoring of sex offenders. In many states, it is now compulsory for sex offenders to undergo polygraph testing before being considered for parole or probation. In some cases, testing is also used to monitor sex offenders. Since these offenders can often re-offend without anyone learning about it for some time, polygraph testing is seen as one way to determine whether a criminal has been rehabilitated or not.

  • By banks. Since bank employees often are responsible for or have access to large amounts of money and other valuables, polygraph testing is used by some to determine employee honesty and in order to run internal investigations.

Many people use polygraph testing: law enforcement agencies, the government, public defenders, attorneys, U.S. and district attorneys offices, parole and probation departments, and companies authorized under the Employee Polygraph Protection Act of 1988 (EPPA).

A free polygraph test resource for businesses

Companies wanting to use polygraph testing themselves need to proceed with extreme caution. While the test is legal, it is highly controversial and must be done completely legally. If not done correctly, a polygraph test can cost a business a great deal in legal costs and in lost reputation. To find an investigative professional who can go beyond the results of a polygraph and find investigators experienced as polygraph examiners, businesses need to look no further than the Worldwide Directory of Private Investigators. The Worldwide Directory of Private Investigators lets businesses look for polygraph experts in their area and even offers free polygraph resources and useful information.

About ( is a Worldwide Directory of Private Investigators that enables law firms, corporations, and the general public to find investigators anywhere. strives to be the most trusted resource on the web to locate qualified investigators. All investigators listed on are pre-screened and must meet specific listing requirements. was developed by the team that brought you the Process Servers Directory (

Visit to find investigators who can help with all your investigation needs.

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