Can an Employer Require a Lie Detector Test?

man getting hooked up to lie detector machineUnder California law, the answer is “no,” and under federal law it’s “probably not.” But some employers still want to give employees a polygraph, lie detector, or similar test.

In California, no private employer may demand or require any employee or job applicant to submit to or take a polygraph, lie detector, or similar test as a condition of employment or continued employment. Lab C §432.2. But that doesn’t mean they can’t ask—as long as the employee is first advised in writing about his or her rights under Lab C §432.2.

Under federal law, the Employee Polygraph Protection Act of 1988 (EPPA) (29 USC §§2001–2009) greatly limits an employer’s ability to polygraph employees. Use of polygraphs as a screening device for job applicants is banned for private employers in most industries. 29 USC §2006(e)–(f). There are potentially steep penalties for violations of the Act (up to $10,000, plus make-whole remedies). 29 USC §2005.

And even if it weren’t legally prohibited, polygraph tests are probably not as effective a tool as many employers imagine. These tests actually measure stress rather than deception. Studies have shown that although the tests do much better than mere chance in detecting deception, they also incorrectly identify many innocent people as liars. That’s why courts generally exclude evidence based on polygraph tests and arbitrators have customarily disfavored them.

In addition to its lack of efficacy, there are other negative factors for polygraph testing:

  • There’s extensive regulation of polygraph testing, which demands careful study and compliance;
  • There are considerable penalties for failure to comply with law governing polygraph testing;
  • Polygraph testing risks the goodwill of innocent employees asked to participate;
  • It may be more difficult to convince a fact-finder there was an independent reason for a later employment decision that was unrelated to the negative polygraph results;
  • The tests are fallible;
  • Polygraph test results are inadmissible as evidence.

But if, despite these factors, an employer still wants to request an employee polygraph test, the employer should get a signed consent form from the employee that explains the use of the test, that it’s not required, and the protection for employees under California and federal law.

For guidance this and other issues relating to workplace privacy, turn to CEB’s Advising California Employers and Employees, chap 13.

Other CEBblog™ posts you may find useful:

© The Regents of the University of California, 2018. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited.

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