It's normal for people to make minor admissions to "control" questions during the pre-test phase. When they do this, the polygrapher moves to contain further admissions, for example by saying: "John, honesty is of utmost importance to this agency. If you can't be honest with your own family, how can we trust you to be honest with us? You haven't lied about anything else, have you?"

Once the examinee answers, "No," the "control" question is re-phrased to exclude any admission(s) that were made, for example, "Other than what you told me, did you ever lie to a loved one?"

It is still expected that the examinee's denial will be untrue, or that he/she will at least be uncertain as to the truthfulness of his/her denial.

See Chapter 3 of The Lie Behind the Lie Detector for further information on polygraph procedure.