Employers: The Polygraph – How much reliance can you place on it?

Labour is highly regulated in South Africa and making mistakes can be a costly exercise. Thus, it is important we get our hiring, promoting and firing correct. Employers have resorted to a variety of techniques to assist them in their decision-making.  One of these techniques is the lie detector test using a polygraph.

Our courts have pronounced on the use of lie detector tests and a recent Labour Court case highlights the importance of not relying exclusively on the lie detector. The polygraph has its place but it needs to be one part of a battery of assessment tools to confirm an opinion or to prove wrongdoing.

The risks of getting this wrong are high!

Apart from the time wasted in preparing for and appearing at hearings, the cost to employers can be high, especially for small businesses.  In the case in question, not only were there legal costs incurred but the Court directed the employer to retrospectively pay the two employees the higher managerial salaries they would have earned had they been promoted.

In the case in question, two employees argued that they were denied promotion as a result of failing lie detector tests (to which they had – as is necessary – consented). They were working for a municipality and when a managerial and a supervisory post respectively became available, they applied for these positions. Whilst other criteria were used in compiling a short list of candidates, including qualifications and work experience, these two candidates failed a polygraph test and did not get the positions.

Critically, the Court found that the municipality “committed an unfair labour practice relating to promotion in relying exclusively on the result of a polygraph test to determine the honesty of the candidates” (author’s underlining).

There have been frequent cases involving fraud (normally a dismissible offence) and the use of polygraphs. The courts have held that “polygraph testing has not been scientifically shown to be a reliable, accurate and valid means of detecting deception” and therefore it cannot be used exclusively to determine an employee’s innocence or guilt. It can however be used to help substantiate a case and the same principle applies in questions of suitability for promotion.

The bottom line

As the Court put it:  “…the exclusive reliance on the polygraph test results to eliminate candidates for appointment on the basis of their deceitful character, in the absence of any other information placing a question mark over their integrity is unfair.”

So be careful – only use a polygraph to bolster your case, not to prove it.

This article first appeared in our CA(SA)DotNews newsletter and is reproduced with authority from DotNews.

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