The admissibility of polygraph tests

When is a polygraph test admissible?

Our case law is uncertain. In misconduct matters an employer must present evidence that it used an outside expert to conduct the lie-detection test that links the employee to the offence.  The person hearing the dispute will decide on the weight to be given to the evidence.  Employers will take a risk if they retrench employees on the ground merely that they declined to submit to a polygraph test.
When is a polygraph test admissible evidence in CCMA proceedings?
The results of a polygraph test should not be admissible if the person who conducted the test is not qualified to testify as an expert about the validity and reliability of polygraph testing in general and the fact that the test in question has been conducted in terms of acceptable standards.
In Truworths Ltd v CCMA and Others (2008) JOL 22565 (LC) the applicant applied to review and set aside an arbitration award.  The test for review is whether the arbitrator’s decision is one which a reasonable decision-maker could not have made.
 The arbitrator had ignored the outcome of a polygraph test despite the fact that a trained polygraphist was called to testify at the arbitration proceedings.
The court stated that “…it cannot be said that a decision was reasonable if the arbitrator disregarded material relevant facts or factors placed before her in coming to a decision.” and held that this was a reviewable irregularity.  This conclusion lead to the review application being granted and the arbitration award set aside.
The lesson is that a commissioner may not disregard polygraph evidence but still has discretion as to how much weight to accord to the evidence. 
What evidentiary weight must a commissioner place on a polygraph test?
Little weight should be given to polygraph evidence when it is not corroborated by further evidence linking the dismissed employee to the offence.  A dismissal based only on polygraph evidence will thus not be upheld.
Does the refusal to submit to a test justify retrenchment?
In SA Transport & Allied Workers Union & Others v Khulani Fidelity Security Services (Pty) Ltd (2011) 32 ILJ 130 (LAC) the employees were contractually obliged to submit to periodic polygraph tests. They refused to do so and were retrenched.  The employees argued that the reason for their dismissal was theft, but the court disagreed and held that “[T]he purpose of the polygraph test was manifestly not to show that theft had actually taken place; it was to test the integrity of all who worked in positions where considerable amounts of theft had previously taken place”.  The court ruled that the retrenchments were fair. However, in National Union of Mineworkers & Others v Coin Security Group (Pty) Ltd t/a Protea Coin Group (2011) 32 ILJ 137 (LC) the labour court expressed misgivings about the correctness of the decision in Khulani although it was bound by it.
The law on this issue is thus not clear and employers should think twice before they follow this route.

Click to view our Website Disclaimer

Leave a Reply

Your email address will not be published. Required fields are marked *