Can polygraph testing assist in curbing workplace crime?

Most companies are continuously considering ways to prevent and address economic crimes perpetuated in the workplace. And, if used correctly, polygraph testing could pose a legitimate solution to mitigate economic crimes in the workplace.

In considering the use of a polygraph test to deter criminal behaviour in the workplace, or to screen prospective employees for a job in a high-risk position of trust, a certain measure of caution must be exercised by employers.

The USA has legislated the circumstances in which employees may be tested and, in the absence of legislation that specifically deals with the subject, South Africa has followed the American procedure as an example of best practice. In addition, legal guidance for the conduct of polygraph tests in South Africa can be found in the Constitution of the Republic of South Africa, 1996 (Constitution), the Labour Relations Act, 1995 (LRA), the Employment Equity Act, 1998 (EEA) and other relevant prescripts/codes of good practices in the workplace.

The Constitution states that everyone has the right to inherent dignity, moreover the right to have their dignity respected and protected. It also provides that everyone has the right to privacy and freedom, including the right of physical security. Forcing an employee to undergo a polygraph test - without their written consent - can be an invasion of that person's constitutional rights.

The Constitution also sets out several labour rights and, in particular, the right every person has to fair labour practices. Accordingly, employers must have regard to rules of fairness, equity and consistency in all their dealings with their employees, not least also when subjecting them to a polygraph test.

In a case where an employee is dismissed based solely on a polygraph finding that suggests that they were dishonest, it is worth noting that the South African courts have found that the sole reliance by an employer on unspecific polygraph test results is insufficient to discharge the onus, as required by the LRA, that the dismissal was fair.

There must be other corroborating evidence, in addition to the polygraph test results, to prove the guilt of an employee and the fact that their subsequent dismissal was fair. To comply with the test of fairness required by the LRA, the Labour Court requires that a polygraph test must be shown to be: scientifically valid and reliable; capable of being fairly applied to employees; and unbiased against any employee or group.

The EEA states that medical and psychological testing of employees and other similar assessments can amount to unfair discrimination in certain circumstances. It has been suggested that the disciplining or dismissal of employees based on the outcome of a polygraph test that is not standardised, and objective could constitute unfair discrimination under the EEA, although that Act does not specifically refer to polygraph testing. 


The credibility of the polygraph test has been disputed and, as such, South African courts have indeed exercised caution when considering its results in workplace labour related disputes.

It is significant to highlight that the polygraph test does not actually detect a lie, but rather the body's psychophysiological response to certain questions.

As such, its accuracy is not always guaranteed. The mental and physical state of the examinee may be influential in the outcome, as may also be the credibility and experience of the examiner; the composition and formulation of the control questions; and the setting in which the test is administered.

Case law has confirmed that polygraph tests are viewed as a subjective interpretation of data. The results of a polygraph test will be regarded as an aggravating factor in sentencing an employee, especially when there is other supporting evidence to corroborate the results.


To protect an employee's right to privacy and to ensure a fair process, it is common practice in South Africa for strict rules to be applied when a voluntary polygraph test is undertaken. The employee must consent – preferably in writing - to undergo a polygraph test and must be informed that the test is voluntary.

Only questions discussed in the pre-test interview may be asked of the employee, and those questions may not be too vague and must be understood by the employee. The employee has the right to request an interpreter or any other person to be present, provided that the person present does not interfere in any way with the proceedings.

Employers often use polygraph tests to investigate specific incidents linked to misconduct, particularly where there is reasonable suspicion that the employee was involved. In addition to making use of a polygraph test in cases involving misconduct, notably other forms of polygraph assessment tests are also being used by some employers.

Depending on the nature of the employment position being offered by the employer, an employee may be requested to undergo a polygraph assessment test to determine their suitability for promotion, or in the case of a prospective employee, whether the person should be employed by the company at all (pre-employment testing).

While the rights of employees are prioritised and guarded, it is also acknowledged that employers need to protect their businesses against increasing incidences of economic crime. Where the polygraph is used as a tool to support and prevent the combatting of crime in the workplace - and where it is administered correctly - our view is that, in answering the question posed in the title of this article, it can play a powerful part in minimising organisational risks if not also "discouraging" misconduct of a criminal nature in our various workplaces.

With acknowledgment of inputs from Terry Booysen, Chief Executive Officer of CGF Research Institute (Pty) Ltd

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