How enforceable is the polygraph in modern-day proceedings?

polygraph test
17 Dec 2021

A polygraph, better known by the public as a “lie detector test”, is used in labour proceedings by an employer to assess the truthfulness of an employee in a dispute or event. The test monitors bodily reactions towards specific questions to determine whether the subject’s blood pressure spikes, there are changes in breathing and sweating on palms.

What are the regulating bodies governing the “polygraph” procedure?

The testing of employees by employers is a very old concept in South Africa. However, there has never been any labour or employment legislation that regulates or controls the use of the test. In addition, no governing body protects the employee’s rights against the employer, who may misuse the test as an excuse to dismiss an employee based on the test results.

Can a polygraph be compulsory?

An employer cannot force a polygraph test. It should always be free and voluntary. An employer conducting a test should ensure that the consent of the employee is obtained in writing and that the possibility of undergoing a polygraph is agreed upon in the employment contract. This will curtail potential disputes.

When is a polygraph appropriate?

As a general practice, employers will usually use polygraph testing to investigate an incident that occurred in the workplace or is related to the employee’s duties.

An employer will usually request that a polygraph test be conducted under the following circumstances:

  • The employee has access to any property that is currently the subject of an investigation;
  • The employee is under investigation for misconduct;
  • Any form of damage, injury or theft from the company that caused financial loss subject to an employee’s actions;
  • Any suspicion of substance abuse;
  • Any fraudulent behaviour that the employer suspects the employee is partaking in or bears knowledge of.

How much weight does the “test” carry in arbitration proceedings?

Every case will be heard on its own merits. However, the commissioner must determine whether or not the test results can be interpreted as guilt or merely a bodily reaction. It can attribute to additional evidence from the employer to strengthen his/her case but will not necessarily stand firm as “proof” of guilt.


There has never been any labour or employment legislation that regulates or controls the use of the polygraph test or protects an employee’s rights against the use of a polygraph test.

Be that as it may, polygraph tests can only be used with the consent of an employee. The polygraph will be taken into consideration in the proceedings but cannot be relied upon by the employer to make its case. It is merely in addition to other evidence.

Contact an attorney at SchoemanLaw for your labour law needs!

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(This article is provided for informational purposes only and not for the purpose of providing legal advice. For more information on the topic, please contact the author/s or the relevant provider.)
Salome Hamman

Salome Hamman graduated with an LLB from the North-West University's Potchefstroom campus. She is a well-rounded, balanced individual with good leadership skills, demonstrated from an early age. She likes to... Read more about Salome Hamman


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