In this series, we will explore some of the ways states vary from one another in their employment laws.

At some point, every employer encounters an applicant or an employee who seems to be stretching the truth, if not telling an outright lie. While some employers might be tempted to test those workers’ truthfulness with a polygraph test, 27 states and the District of Columbia place restrictions on private employers’ use of lie detectors.

Of course, the devil is in the details, and not all of these state restrictions are the same. Most of these states restrict all private employer demands or requests that an applicant or employee submit to a polygraph test. However, some states are broader in their restrictions. For example, Massachusetts defines “lie detector” more expansively than just a polygraph test and also includes any “device, mechanism, instrument or written examination” used to detect deception, and multiple lawsuits have been filed over the question of whether artificial intelligence scans of recorded interviews constitute “lie detectors” under state law.

Other states are narrower in their restrictions. Virginia does not have across-the-board restrictions on private employers’ use of polygraph tests. It only prohibits employers from asking prospective employees about sexual activities. Tennessee and Illinois also place specific limitations on certain sensitive topics instead of prohibiting all polygraph tests.

A few states not only prohibit the use of lie detector tests, but also place affirmative obligations on employers to notify applicants that they will not use such tests. Maryland and Massachusetts, for example, both have specific requirements for employment applications. Employers must conspicuously state that no lie detector tests will be required.