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Polygraph testing, commonly referred to as a “lie detector test,” is a specialized tool used by employers to verify truthfulness during workplace investigations. While its use is becoming more frequent in South Africa, it is not governed by any specific labour legislation. Instead, its application is guided by the Constitution and established case law from the CCMA and Labour Court.

1. Can an Employee Be Forced to Take a Polygraph Test?

No employee can be compelled to undergo a polygraph examination against their will. Testing is strictly voluntary unless a written collective agreement or an employment contract specifically provides for it.

Even if a contract exists, the employer must inform the employee of the following rights before the test begins:

• The examination is voluntary.
• Only questions discussed and agreed upon prior to the test will be used.
• The right to an interpreter if required.
• The right to have another person present (provided they do not interfere).
• A guarantee that no abuse, discrimination, or threats will be tolerated.

2. When is an Employer Permitted to Use Polygraph Testing?

Employers are generally permitted to use polygraph tests to investigate specific workplace incidents, including:

• Theft or Loss: Investigations into economic loss, injury to the business, or theft where the employee had access to the property.
• Reasonable Suspicion: When there is a justifiable belief that the employee was involved in an incident.
• Positions of Trust: Combating dishonesty in senior or high-responsibility roles.
• Serious Misconduct: Investigating fraudulent behavior, falsification of documents, or substance abuse within the company.

3. The Status of Polygraph Evidence at the CCMA

It is a common misconception that failing a polygraph test is conclusive proof of guilt. At the CCMA, polygraph results are treated as expert evidence that must be tested for reliability.

• Not 100% Accurate: The CCMA recognizes that polygraph tests are not entirely reliable and cannot be used as the sole basis for dismissal.
• Supporting Evidence Only: Test results are used to support or corroborate other available evidence that suggests misconduct.
• Determining Probabilities: Results are one factor used by commissioners to determine the balance of probabilities rather than providing definitive proof of an act or omission.

4. Access to Results

Polygraph results are highly confidential and can only be released to authorised persons:

• The person who underwent the test (the examinee).
• Anyone specifically designated in writing by the examinee.
• The authorized employer representative or government agency that requested the test.