SDPD Polygraph Screening Documents Disclosed

AntiPolygraph.org has published a set of documents concerning the San Diego Police Department’s polygraph practices. These documents, which date to 2017, focus primarily on pre-employment polygraph screening.

The most notable document, titled “SDPD DLST Preemployment Script” instructs the polygraph operator how to conduct the “pre-test” procedure.

“DLST” stands for “directed-lie screening test.” Directed-lie “control” questions are ones in response to which the examinee is told to “lie,” unlike probable-lie “control” questions, in which the operator attempts to manipulate the examinee into lying. For more on directed-lie “control” questions, see Chapter 3 of The Lie Behind the Lie Detector (beginning at p. 107 of the 5th edition).

The pre-employment script shows that the “test” consists of a “Subtest A” and a “Subtest B.” The relevant questions on Subtest A are:

R1 As an adult, have you received any (other) formal discipline at work?

R2 As an adult / In the last 10 years, have you had any (other) personal involvement with illegal drugs?

There is also an unscored “sacrifice relevant” question:

SR Do you intend to answer the formal discipline and drug involvement questions truthfully?

The directed-lie “control” questions are:

C1 Did you ever lose your temper?

C2 Did you ever violate a minor traffic law?

There are also two irrelevant, or in SDPD’s parlance, “neutral” questions. These are not scored:

N1 Are you now in San Diego?

N2 Are the lights on?

Subtest B includes the following relevant questions:

R3 Have you ever committed any (other) serious crime?

R4 Have you ever committed any (other) sex crime?

The sacrifice relevant question for Subtest B is:

SR Do you intend to answer the “serious crime” and “sex crime” questions truthfully?

The directed-lie “control” questions for Subtest B are:

C3 Did you ever say anything about someone that wasn’t true?

C4 Did you ever violate a rule or regulation?

And finally, the irrelevant questions for Subtest B are:

N3 Are you now sitting down?

N4 Is today _____?

For more details, see the SDPD DLST Preemployment Script.

The document collection also includes a “polygraph questionnaire” with many more questions than the four relevant ones that are asked while the subject is hooked up to the polygraph instrument, a set of “mind maps” that describe the scope of the relevant questions from Subtests A and B, as well as a script used for polygraphic interrogation of criminal suspects.

It should be borne in mind that polygraphy has no scientific basis, and it is common for truthful people to wrongly be branded as liars. If you are facing a polygraph “test,” be it with the San Diego Police Department or any other agency, be sure to download a copy of The Lie Behind the Lie Detector for more on polygraphy’s scientific shortcomings, the simplistic methodology on which it relies, and pointers on what you can do to mitigate the risk of wrongly failing when you’re telling the truth.