Some people fail due to high anxiety or guilty conscious. You are told not to overthink a question because you can fail the test. However, the test is easily passed if you do it right and you can lie through the test. The lie detector test is used for questions involving assaulting people, drugs, and child crimes. Should it still be used?
The RESULTS of a lie detector test cannot be used in count *as evidence*. HOWEVER any statements (or confessions) can be used as evidence regardless of if the results said it was a lie or not. Since the results of lie detector tests are unreliable, instead we can think of lie detector tests as interrogations that pressure people to tell the truth.