As an employer, maintaining a harmonious and productive workplace is essential for the success of your business. Unfortunately, there may be times when misconduct occurs, and you find yourself in the dark about who is responsible.
This is where polygraph testing can become a potentially valuable tool for employers. Polygraphs can be used during the investigation phase to assist the employer in identifying the misbehaving employee. They may also be used during the subsequent disciplinary hearing as evidence against the employee.
It is crucial to understand how polygraphs may and may not be used to stay within the bounds of the law. Let’s examine the critical factors employers must be aware of.

Agreement on the use of polygraph testing.
Employees must agree to undergo polygraph testing through a clause in their employment contracts, or if their contracts do not expressly provide for polygraph testing, they must agree in writing before any such test is conducted.
Employees may legally refuse to take such tests when the employment contract does not expressly allow for polygraph testing. Employers may not make a negative deduction or take disciplinary action against the employee based on the refusal.
Where the employment contract does expressly allow for polygraph testing, employees may not legally refuse to take such tests when instructed to do so. Employers may also take disciplinary actions against an employee who refuses the instruction to take the test.
Employers are, therefore, strongly advised to include polygraph test clauses in their employment contracts.

Polygraph evidence by itself is insufficient.
Evidence of a failed polygraph test by itself during a disciplinary hearing is insufficient evidence to find an employee guilty of misconduct. Polygraph results must always be led with other forms of evidence, such as verbal evidence from witnesses, documentary evidence, video footage and circumstantial evidence.
Thorough investigation.
Employers should conduct a thorough and diligent investigation, gathering as much evidence of the alleged misconduct as possible. Relying solely on polygraph results is not a recommended practice.
Expert Testimony.
When polygraph evidence is presented as evidence during a disciplinary hearing or a subsequent arbitration, it must be done through the expert witness testimony of the polygraph examiner who conducted the polygraph test. Without this testimony, the polygraph evidence will not be admissible.
It is, therefore, important for employers who engage the services of polygraph examiners to ensure that the examiner is suitably qualified and that the service package they buy includes the examiner’s testimony at the hearing and the subsequent arbitration, should this be necessary.

Conclusion.
Polygraph testing can be helpful for employers during investigations and disciplinary hearings for workplace misconduct. It is not a silver bullet and must always be supported by a thorough investigation and good supporting evidence.
Employers whose employment contracts lack a polygraph clause should correct this oversight immediately.
Thank you for this thorough article.