June 20, 2017


Polygraph tests are frequently employed by employers in instances where they wish to verify whether the truth is being presented by a testee/employee in a particular circumstance or not.   The result of a polygraph shows whether the responses of a testee indicate deception, no deception is indicated or whether the responses are inconclusive.  Typical instances in which polygraphs are utilised are where a theft is suspected in an organisation or whether an employee/s have knowledge of other employees involvement and complicity in such a transgression, disappearance of petty cash or colleagues possessions and they are sometimes even used to assess candidates earmarked for promotion.

Polygraph testing on its own has limited evidential value in any dispute such as an unfair dismissal dispute.  It, at most, has corroborative value.  This means that the results of a polygraph test cannot be utilised as the sole and only pieces of evidence at a disciplinary hearing, as an example, for unauthorised removal of company property which may result in the termination of the employee’s services.  They have corroborative value to the extent that there is other available evidence that corroborates a deceptive polygraph test result.  This evidence would include a broad range of possible forms of documentary records and evidence.  It does not imply that a polygraph test should not be administered.  It implies that any initiator of a disciplinary hearing would be obliged to seek out and present other forms of supporting evidence for the results of a polygraph test, if this evidence is to be regarded and considered by the chairperson of a disciplinary hearing to have sound evidential value.   This principle was established in Food and Allied Workers Union obo Kapesi and Others v Premier Foods Ltd t/a Blue Ribbon Salt River (2010) 31 ILJ 1654 (LC).

It is common practice for employers to set, as a material condition of employment in contracts of employment, that it is essential that any recruited employee be willing to under a polygraph test should the employer deem this necessary.   What happens if an employee, under such circumstances, elects not to undergo the polygraph test relying on the fact that it is their constitutional right to refuse to do so.  In SA Transport and Allied Workers Union v Khulani Fidelity Security Services Pty Ltd (2011) 32 ILJ 130 (LAC) the Labour Appeal Court found that a dismissal on the basis of operational requirements could be justified in the situation where the employee’s contract of employment required him/her to undergo a polygraph test.  However, one must be sure that in executing an operational requirements related termination that one does not base such decisions on the basis of an employee’s deceptive polygraph test results, as this would be deemed to be an unfair selection criteria for executing a retrenchment as was determined in the NUM & Others v Coin Security Group Pty Ltd t/a Protea Coin Group (2011) 32 ILJ 137 (LC).  So it is fair to retrench an employee whose contract of employment spells out that that employee is obliged to submit to a polygraph test at the instance of the employer, but it is not fair to retrench an employee by applying the deceptive results of a polygraph test as the selection criteria for that retrenchment.

Having regard to such jurisprudence, and there are several others which are relevant to this topic, employers are to carefully consider the holistic picture before relying solely on the results of a polygraph test in attempting to secure the termination of an employee’s contract of employment and defending such a dismissal decision in any unfair dismissal dispute.  It would be necessary to ensure that other forms of corroborating evidence is available and presented to the presiding officer before being able to rely solidly on the evidential value and credibility of a polygraph test.

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