Notes: The Deception of Polygraph Testing — As a Test for Deception

Authors Reynaud Daniels & Jeremy Phillips

ISSN: 2413-9874
Affiliations: BA (University of Cape Town); LLB (University of the Western Cape); Director, Cheadle Thompson & Haysom Inc (CTH); BA LLB (University of Cape Town); LLM (University of Fort Hare); Associate, CTH
Source: Industrial Law Journal, Volume 44 Issue 4, 2023, p. 2139 – 2150


Polygraph testing is a common tool utilised by employers to investigate suspected misconduct and maintain discipline in the workplace. It delivers a definitive answer one way or another on whether a suspected employee is guilty. However, it does not do so accurately or reliably. Experts have estimated that about half of the time, the polygraph returns a false negative, which often leads to disciplinary action, and even dismissal. For this reason, the Labour Court and Labour Appeal Court have warned against the admission of polygraph evidence, and the weight attributed to it. Despite this, commissioners (and occasionally judges) afford polygraph evidence far greater status than deserved or permitted. Its evidential yield is so negligible, and its results so unreliable, that its admission as evidence cannot be justified.