Polygraph experts continued to fine-tune the machines, and also developed a questioning technique that was intended to produce fewer incorrect readings (the subject is asked to respond "yes" or "no" to questions, and unrelated questions are mixed in with relevant ones; this is meant to eliminate nervous affect).

In 1975, federal judges were given more discretion about the admissibility of evidence under new "Federal Rules of Evidence." Thus, a judge could allow a jury to consider polygraph results even if they did not pass the Frye Test. In 1993, the U.S. Supreme Court issued an opinion on Daubert v. Merrell Dow Phramaceuticals that definitively replaced the Frye standard. The court said that judges could admit certain scientific evidence as long as the theory behind it could be been tested, it had been subject to peer review and publication, the potential error was known, and the scientific community in general accepted the theory. In the 1998 case of U.S. v. Scheffer, the U.S. Supreme Court ruled that polygraph tests did not have to be admitted as evidence in military trials. (President George H.W. Bush had banned the admission of polygraph evidence from military trials in 1991, citing their unreliability.) But it did not ban polygraph evidence outright. Daubert grants judges the right to determine whether polygraph evidence can be used or ignored, so it is generally up to the judge.

The polygraph has also been used to pre-screen job applicants or to test employees to measure their truthfulness about such issues as drug use or theft. In 1988 Congress passed the Employee Polygraph Protection Act (EPPA), which prohibited business from using polygraph evidence to pre-screen employees or to test current employees, and which prohibited companies from disciplining or firing employees solely for failing a polygraph test. (Polygraphs can be used if an employer can show other evidence against an employee, but the employee still has the right to refuse.) EPPA does not apply to government workers.