Polygraph tests in the workplace

Polygraph tests in the workplace


Employers are frequently under the impression that when an employee fails a polygraph test it is sufficient grounds to justify the dismissal of an employee. This is in fact not the case when studying case law as handed down by our Labour Courts and as a result there are certain requirements employers should take into account when considering the usage of polygraph tests.

Useful guidelines for polygraph testing in the workplace.

Employees should agree before being subjected to these tests and are protected by two constitutional rights:

  1. Section 14 – the right to privacy
  2. Section 15 – the right to not incriminate oneself

If it is however stipulated in the contract of employment that an employee must undergo a polygraph test when there is grounds for suspicion the refusal of an employee to subject himself can lead to disciplinary action against the said employee.

If the employer proceed with the test either with the permission of the employee or as a result of the contractual obligation on the employee there are still some requirements the employers should comply with:

  • The employer should inform the employee that there is no obligation on him/her to subject themselves unless if there is a contractual obligation on them.
  • The employee should be informed that he/she has the right to an interpreter.
  • That he/she can be accompanied to the test by a person who won’t be allowed to intervene.

When the test is finalised and there is an indication of deception the employer must call the examiner to testify at the disciplinary hearing. If there is no such testimony the evidence will be insufficient.

As can be seen in the following case law polygraph tests by itself are not sufficient evidence to institute disciplinary action against an employee.

In Sobiso & Others v Ceramic Tile Market the court came to the conclusion that the test is only an indication of deception and the sole reliance on the test result is insufficient to discharge the onus of prove on the employer.

In Amalgamated Pharmaceuticals Ltd v Grobler NO and others the court also came to the conclusion that a polygraph test is not sufficient to prove guilt and that it’s only an indication of deception.

As a result of the above employers should keep in mind to follow the correct procedures when deciding on these tests and to rely on supporting evidence at the disciplinary hearing.


Ruan Vlok obtained his LLB degree from the University of the Free State and was admitted as an Attorney of the High Court of South Africa in April 2015. He is currently a SEESA BEE & Labour Legal Advisor and has been with SEESA for approximately 2 years.



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