Bruno,

You are confused on the concept of time bars. Time bars are used to limit the scope of a question. They are especially used to limit the scope of probable-lie "control" questions in incident-specific (criminal) polygraph interrogations, but may also be used to limit the scope of relevant questions.

You seem to be seeking a simplistic rule for identifying "control" vs. relevant questions. No such rule exists. If an agency's policy on drug use were that the applicant must not have used any illegal drug within the past three years, then a relevant question could conceivably be time-barred, e.g., "In the past three years, did you use any illegal drug?" But the presence of the time bar does not per se make the question a relevant one.

With regard to stealing from an employer, probable-lie "control" questions in this regard are generally not time-barred. Nonetheless, if you were asked, "Have you stolen from an employer in the past three years?" the question would remain a probable-lie "control" question.

What could possibly change a question about theft from an employer to a relevant question is if the question were about theft of money (always a relevant question) or if it pertained to theft of items over a high dollar amount.

In distinguishing between probable-lie "control" questions and relevant questions, it is crucial that one understand the rationale for probable-lie "control" questions, which is discussed in Chapter 3 of The Lie Behind the Lie Detector. This has also been the topic of recent discussion on this forum, and you might want to review recent posts in this regard. In addition, for further reading on "control" questions, see Chapter 8 of David T. Lykken's book, A Tremor in the Blood: Uses and Abuses of the Lie Detector (2nd edition, Plenum Trade, 1998).