Everything you need to know about using a polygraph test to determine workplace misconduct

An employer in pursuit of finding the truth should use polygraph tests cautiously.

  • By Fasken partner Ludwig Frahm-Arp, associate Tshepiso Rasetlola and candidate attorney Catherine Hendriks

Employers are regularly faced with situations in which something happens at the workplace that would constitute misconduct if committed by the employees of the employer.

For example, stock goes missing from a storeroom, and there is no evidence of a break-in and only a handful of the employees had access to the storeroom.

In this instance, one would have to assume that the stock must have been taken by one of the employees working in the storeroom.

The challenge would be how the employer identifies and determines who among the group of employees is responsible for the missing stock when there is no direct evidence from the facts linking a particular employee to the missing stock. How does the employer go about identifying who among their employees took the stock?

Polygraph testing
In these circumstances, employers often resort to subjecting their employees to polygraph tests and then disciplining and dismissing those employees who “fail” the test, only to find that the dismissals are ultimately found to be unfair before the Commission for Conciliation Mediation and Arbitration (CCMA).

In the case of Goldplat Recovery (Pty) Ltd v Commission for Conciliation Mediation and Arbitration & Others (unreported case no. JR488/2019, 26 January 2021), the Labour Court had to deal with an issue where an employer dismissed an employee based solely on a polygraph test result.

In order to establish how an employee gained access to the restricted area, which enabled him to get possession of R850,000 worth of the gold concentrate, Goldplat subjected each of the employees who worked in the restricted area to a polygraph test. Mr Maziya, the complainant, “failed” the test and was subsequently charged with misconduct and ultimately dismissed.

Mr Maziya referred an unfair dismissal dispute to the CCMA, where the Commissioner found his dismissal to be unfair and awarded him maximum compensation. The Commissioner found no direct evidence that implicated Mr Maziya and the assumption made by Goldplat that he was guilty by virtue of failing his polygraph test was mere speculation.

Dissatisfied with the findings, Goldplat launched an application before the Labour Court seeking to review the Commissioner’s award; however, the Labour Court upheld the Commissioner’s findings and dismissed the review application with costs.

Evidentiary value of Polygraph Tests
In light of the Goldplat case, this then begs the question, can polygraph tests be used in establishing that an employee committed misconduct, and if so, in what circumstances.

There is currently no legislation regulating the use of polygraphs in South Africa.

The use of evidence from polygraph tests can only be corroborative or serve to assess probabilities such as the credibility of a witness in cases where an employer has to justify dismissal. There is, therefore, nothing prohibiting or preventing the submission of polygraph results to corroborate other evidence.

In dealing with evidence from polygraph tests, the courts have had to navigate through the controversy by developing principles to apply when approached with matters involving the use of evidence from polygraphs tests. Much of the controversy surrounding polygraphs stems from the accuracy of this tool.

That being said, polygraph tests can be used and are admissible as evidence but any judge or commissioner relying on such evidence must treat it very cautiously. In order for your polygraph evidence to be admissible, you need to call the polygrapher as a witness to explain how the tests are done, what he did, and what the results were.

A contributory factor to the court finding against Goldplat was its failure to call the polygrapher as an expert witness. Polygraph tests are not direct evidence, only circumstantial evidence, therefore on their own they are not evidence of anything.

They can be used as a final piece in the jigsaw puzzle to prove the employee’s guilt (to corroborate the other evidence or the conclusions drawn from the other evidence), but they cannot be the cornerstone on which the case is built. One cannot be guilty of the misconduct simply and solely because they “failed” a polygraph test.

Refusal to undergo polygraph testing by employee
What can you do if the employees refuse to undergo the polygraph test? Can this be used as evidence of guilt? As stated in Goldplat, the onus rests on the employer to prove the employee’s guilt and not on the employee to prove their innocence. The employer, however, cannot force any employee to submit to such a test. Refusal to do so does not indicate guilt and is also not grounds for dismissal.

Thus, the employer must obtain consent. If an employee refuses to consent and finds himself dismissed based on this refusal, the dismissal is likely to be a ground of unfair dismissal against the employer.

However, the refusal to undergo the polygraph test can be used as circumstantial evidence. This means that an adverse inference may be drawn from the employee’s refusal to take a polygraph test.

For example, where there is direct evidence placing the employee in the vicinity of the storeroom on the day the stock was stolen. The other employees are all able to account for their whereabouts on the day and were not near the storeroom. All the other employees underwent polygraph tests and “passed”. The employee refused to undergo the polygraph test. In those circumstances, the employee’s refusal can be considered in weighing up the probabilities that the employee is guilty of the misconduct.

An employer in pursuit of finding the truth should use polygraph tests cautiously. Nothing is worse than having the employee “fail” the polygraph test but having no other evidence to prove their guilt and so not being able to proceed against them.

The sole reliance on failed polygraph tests will be insufficient to prove that an employee is guilty of misconduct or has lied. A polygraph test can only be used to corroborate any other evidence that demonstrates that an employee is guilty of misconduct.

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