Unit 4: Selection and Crime Scene Process

The Polygraph Examination

Unlike most private employers who cannot screen applicants by use of the polygraph, many police agencies can, and do, administer this examination. The polygraph is helpful to law enforcement agencies for several reasons: it screens out some of the undesirable applicants who otherwise might make it to the background examination; it identifies candidates who are not serious about a law enforcement career; and, it identifies the user-agency as one which is serious about hiring only the best candidates.

The polygraph is a device which records the examinees responses to questions on a roll of paper. It measures breathing, pulse and blood pressure, and the skin’s resistance to an electrical current. Many applicants have been eliminated by this procedure. Often the reason is not the applicant’s lying during the polygraph examination but untruths that were written on the application or told during the oral examination. These often involve questions regarding former drug use. More on this in a later Unit.