Use of the Polygraph to Screen Police Candidates

Police departments have an obligation to protect the citizens of their community and the reputation of their agency. An important administrative function that supports that obligation is the hiring process. The police department must fill open positions in order to fulfill its public safety roll, while ensuring that inappropriate candidates are screened out. Some police departments use the polygraph test as a screening device. The Employee Polygraph Protection Act of 1988 prohibits employers from using the polygraph test as a pre-employment screening tool (https://www.dol.gov/whd/polygraph/). Police departments are exempt from this law. The Texas Commission on Law Enforcement requires that a background investigation be conducted on candidates but does not require that a polygraph test be administered. Polygraph test results can only be introduced as evidence in court under limited circumstances. While the polygraph test has proven to be an effective law enforcement investigative tool, it is not infallible. The polygraph test results can be intentionally or inadvertently manipulated. Errors, especially a bias toward false positive determinations, can have a negative impact upon the police department and the candidate. Police departments should not use the result of a pre-employment polygraph test as the sole basis of a negative hiring decision