A polygraph examination concerned with integrity while a person is employed. The questions relate to honesty in the work itself, such as duties, property, or information an employer has entrusted to them. It is used when that workplace matter is what needs to be examined. The examination does not replace the employer's own decision.
A polygraph examination carried out before a person is employed. It asks integrity questions during hiring, before the person starts the role. An employer may use it as one step in choosing whether to take someone on. It does not, by itself, decide that someone is hired.
A polygraph examination repeated at intervals for people who are already employed. It is a scheduled examination, rather than one arranged because of a single event, so integrity questions can be asked again after a period of time has passed.
A polygraph examination directed at one stated issue. The questions stay with that matter, such as one incident or one allegation, instead of ranging over a person's employment in general. It is used when the concern is specific.