Polygraphs - friend or foe?
Johanette Rheeder

Employers are often faced with dishonest or criminal activities such as fraud or theft, without knowing exactly where, how and by whom it was committed. It can have a crippling effect on the employer’s business. Often the employer is at its wits-end to find the culprits or wants to know: “Can I send all my employees for a polygraph test and if so, what can I do if they fail?” if the answer is yes, then what do we need to do in order for the results to stand up in a disciplinary hearing or arbitration?

Polygraphs are often also referred to as a lie detector test and is an instrument that measures and records several physiological responses to questions asked by the examiner, such as blood pressure, pulse, respiration, breathing rhythms, body temperature and skin conductivity. This is based on the theory that false answers will produce distinctive measurements which are picked up by the polygraph device. A great controversy in respect of polygraph testing lies in the different views of experts about the accuracy of the test. In the case of Kapsi (discussed later in this article), the expert witnesses agreed that the crucial variable is the examiner and that the composition and formulation of the control questions are crucial. In respect of the South African context, one of the factors which may affect physiological responses in a polygraph test for deception is that of racial stigmatisation. Some studies in South Africa pointed out that if either the examiner or the examinee is a member of a stigmatised group, the examinee may show heightened physiological responses particularly during difficult aspects of the testing situation.



In the United States of America, the use of polygraph tests are restricted in the private sector by way of the Employee Polygraph Protection Act of 1988 (EPPA). This piece of legislation prevents employers from using polygraph tests, either for pre-employment screening or during the course of employment. Under the EPPA, most private employers may not require or request any employee or job applicant to take a polygraph test, or dismiss, discipline, or discriminate against an employee or job applicant for refusing to take a test or for exercising other rights under the Act. The EPPA however does allow for certain exemptions and permits polygraph tests to be administered to certain applicants for jobs such as security firms and pharmaceutical manufacturers and distributors. In the case of such exceptions, strong safeguards are in place via the legislation.

In South Africa, we do not have specific legislation regulating the polygraph industry, nor the rules regarding testing. No reference is made in any labour legislation to polygraph testing as well. We are however not completely without protection. The principles that apply to, and have been accepted by our courts relating to polygraph testing, can be derived from chapter two of the Bill of Rights contained in the Constitution. Section 10 states that everyone has the right to inherent dignity and the right to have their dignity respected and protected. A person can therefore not be physically forced to subject himself to a polygraph test. Section 12 also grants security in and control over the person’s own body and the right not to be subjected to medical or scientific experiments without informed consent.
Section 23 sets out a number of labour rights, most importantly the right every person has to fair labour practices.
In general, all the rules relating to fairness will apply to any employer who wants to test employees or who wants to screen, act, discipline or dismiss employees or job applicants. Polygraph examiners should understand and respect these rules of fairness, as their conduct may render the results inadmissible or alternatively can add to unfair conduct or treatment of the employee.


It is against the Constitution of South Africa to compel a person to undergo a polygraph examination, unless she consents to it. The consent must be in writing. The individual should be informed that—

the examinations are voluntary;

only questions discussed prior to the examination will be used;

the employee has a right to have an interpreter, if necessary;

should he prefer, another person may be present during the examination,

provided that person does not interfere in any way with the proceedings;


Polygraph tests are used by law enforcement agencies, the legal community, and the private sector such as companies, agencies, employers and private citizens. Generally, employers use the polygraph test to investigate specific incidents where employees had access to the property which is the subject of the investigation and there is reasonable suspicion that the employee was involved in the incident.

Generally, employers use the polygraph to investigate specific incidents where—

  • Employees had access to the property which is the subject of the investigation;
  • There is a reasonable suspicion that the employee was involved in the incident;
  • There has been economic loss or injury to the employer's business like theft of company property;
  • The employer is combating dishonesty in positions of trust;
  • The employer is combating serious alcohol, illegal drugs or narcotics abuse or fraudulent behaviour within the company;
  • The employer is combating deliberate falsification of documents and lies regarding true identity of the people involved.
  • Criminal behaviour or offences.

Polygraph testing is also used for criminal cases such as theft, fraud, assault and marital infidelity or child abuse, to name but a few.

In the USA the regulations stipulate that the results can only be released to authorised persons, however we do not have those regulations in South Africa. However, polygraph results should not be released to any person but only to an authorised person. Generally it is the person specifically designated in writing by the employer whom requested the examination. During court and CCMA processes, polygraphists have been accepted as expert witnesses whose evidence needs to be tested for reliability. Therefore the polygraphists should be called to testify as an expert witness in the disciplinary hearing or the CCMA. He must testify on his skill, qualification and experience, the procedure he followed, how the test was performed, the type of test used and the questions asked. He must testify on the outcome of his report and why he came to the conclusions he did. If necessary, a medical doctor should also testify on the issue of manipulating body functions to mislead the polygraphists, if that becomes an issue at the hearing.


In Amalgamated Pharmaceuticals Ltd v Grobler NO and others (2004) 13 LC 1.11.3 the court confirmed the principle that, in practice, a polygraph does not serve to prove that someone is actually lying and the questions are often too broad to exclude that which is neither intended nor sought. The court found that it most definitely does not prove that someone is guilty. It is merely an indication of deception. The sole reliance by the employer on unspecific polygraph results is insufficient to discharge the onus in terms of section 192 of the Labour Relations Act 66 of 1995, to prove that the dismissal was fair. To discharge this onus, the test of a balance of probabilities is used. To only present polygraph evidence is not enough to show that the dismissal was fair because there is no corroborating evidence. In the more recent case of FAWU obo Kapesi & others v Premier Foods Ltd t/a Blue Ribbon Salt River (2010) 19 LC 9.5.1 and reported in [2010]BLLR 903(LC), the Labour Court considered the weight a court must attach to polygraph results. The court accepted from the onset that polygraph testing, although frequently used in the context of workplace discipline, is by no means uncontroversial. It found that, a polygraph on its own can never be conclusive proof of the guilt of an employee. At best the polygraph on its own could be used as part of the investigation process to determine whether or not a further investigation into the conduct of a particular individual is warranted.

Does that mean that an employer cannot use polygraph testing? No, it does not, however there are some strict rules of fairness relating to polygraph tests that need to be adhered to by the polygraph examiner and the employer, unless the employer wants the test results to be found unreliable, unfairly applied and useless in the CCMA or the Labour Court! In essence, to comply with the test of fairness, the labour court held that the test or assessment used would need to be: (i) shown to be scientifically valid and reliable; (ii) shown to be capable of being fairly applied to employees; (iii) shown to not be biased against any employee or group.

In the CCMA, polygraphists have been accepted as expert witnesses whose evidence needs to be tested for reliability. The duty of the commissioner is to determine the admissibility and reliability of the evidence. Polygraph test results may not be interpreted as implying guilt but may be regarded as an aggravating factor especially where there is other evidence of misconduct. In other words, polygraph test results, on its own, are not a basis for a finding of guilt in the CCMA. It can be used only in support of other evidence.


What appears from the aforegoing is that a polygraph test on its own cannot be used to determine the guilt of an employee. It is indicative of deception only and the accuracy depends on the examiner and the control questions asked. However, a polygraph may be taken into consideration where other supporting evidence is available, provided also that there is clear evidence on the qualifications of the polygraphist and provided that it is clear from the evidence that the test was done according to acceptable and recognisable standards. At the very least, the result of a properly conducted polygraph is evidence in corroboration of the employer’s evidence and may also be taken into account as a factor in assessing the credibility of a witness and in assessing the probabilities of the versions before the court. The mere fact that an employee refuses to undergo a polygraph is not in itself sufficient to substantiate an employee’s guilt.

For more information contact Johanette Rheeder on This email address is being protected from spambots. You need JavaScript enabled to view it.