Polygraphs are a relatively credible means of detecting deception. However, the accuracy of lie detector tests depends on various factors, including how the questions are framed.
It’s probably common knowledge that polygraph questions should be relevant to the specific matter under investigation. But relevance isn’t the only cardinal rule when designing polygraph questions.
To conduct a reliable lie detector test, an examiner must adhere to several other principles.
Here’s a guide to the industry’s best practices when crafting polygraph questions.
Rule #1: Relevance
As already mentioned, polygraph questions should be relevant to the matter being investigated. Do not go off on a tangent when administering a lie detector test.
For instance, questions pertaining to an examinee’s sex life would be immaterial when investigating a workplace theft.
Asking too many irrelevant questions is time-wasting. And as you can see, polygraphs should comply with specific timing requirements.
Rule #2: Diversity
While polygraph questions should be restricted to the specific matter under investigation, the questions must be split into various categories as follows:
1. Relevant Questions
Relevant polygraph questions directly address the subject at hand. Examples include:
Did you steal $200 from your manager’s desk yesterday? (For workplace polygraph testing)
During your trip to (COUNTRY NAME) on (DATE), did you share sensitive government secrets with authorities there? (For counter-surveillance testing)
Since (ENTER DATE), have you had sexual contact with anyone besides your current partner? (For sexual infidelity testing)
2. Control Questions
Control questions relate to similar but less severe crimes committed by an individual in the past. The idea is to compare the examinee’s response to these past misdeeds with relevant questions.
A stronger response to control than relevant questions indicate truthfulness, while the converse suggests deception.
Examples of control questions include:
- Have you ever lied to avoid trouble?
- Have you ever done something at work that you could have been fired for?
3. Irrelevant Questions
While this may sound counterintuitive (considering that all polygraph questions should be subject-specific), irrelevant questions help the examinee relax after periods of intense questioning. They typically address general information, such as:
Is your name Tom?
Are you originally from Minnesota?
Since the different categories of polygraph questions are covered, let’s proceed further and understand how every question must be phrased to maintain standards and accuracy.
Rule #3: Dichotomy
According to the American Polygraph Association (APA) question formulation standards, polygraph questions should elicit a flat “Yes” or “No” answer.
Do not ask questions requiring narrative replies.
Usually, “yes” answers are expected when polygraphing victims and witnesses, whereas “no” responses are expected from suspects.
Rule #4: Brevity and Unambiguity
Polygraph questions should be concise. Long-winding, overly wordy statements aren’t allowed.
Lie detector questions must also be straightforward, not subjective. In other words, there should only be one interpretation of the question.
Assume you’re polygraphing an individual on a recent robbery at Mr. Humphrey’s residence. Instead of simply asking “Did you commit a robbery this week?” consider a more direct statement like “Did you rob Mr. Humphrey’s of $400 on (DATE)?
Rule #5: Clarity
Despite the widespread use of polygraphs in criminal defense testing, the questions should be free from legal and technical jargon. Each question must be understood by the examinee right away.
Legal jargon like “homicide” or “assault” should be replaced by simpler alternatives, such as ‘stab’ and ‘shoot.’
Rule #6: Non-inflammatory
Avoid inflammatory or sensitive words when framing polygraph questions.
Instead of “rape,” consider ‘sexual contact.’
But in the interest of unambiguity, it’s best to specify the nature of the offense. For instance, “Did you have oral sex with Billy yesterday?”
Rule #7: Non-speculativeness
Another round of polygraph questions to avoid are those containing leading or speculative statements.
Don’t ask – “Did you plan to kill your wife when you discovered she was cheating on you?”
Even if the answer is yes, it doesn’t exactly confirm that the defendant committed homicide.
Rule #8: Number of Questions
The number of polygraph questions to ask depends on the specific type of testing.
1. Single Issue Exams
Single-issue polygraphs seek to resolve one issue. Here, just one question would suffice.
2. Multi-Facet Exams
Multi-facet polygraph evaluations are meant to resolve one issue by asking multiple related questions. You could ask up to three queries.
3. Exploratory Exams
These lie detector tests seek to resolve up to four different but closely related issues. They typically attract up to four relevant questions for each issue.
4. Statement Verification Exams
As the name implies, statement verification polygraphs attempt to validate the truthfulness of a written statement, such as a disclosure.
A polygrapher may simply pose a single question like “Did you lie about anything in your disclosure statement?”
Rule #9: Timeliness
Polygraph tests should take an average of 1.5 to 2.5 hours. That’s enough to ask a significant number of relevant, control, and general questions.
Rule #10: Fair Hearing
After the culmination of each lie detector test, the examinee must be allowed to explain their answers. This is necessary before compiling the full report.
Enhancing the Credibility of Polygraph Tests with Professionally Designed Questions
Implementing this policy while drafting polygraph questions can be significant in conducting reliable and legally defensible lie detector tests. As a parting shot, remember to also address various ethical issues surrounding polygraphs.
Lie detector tests are considered ethically administered if the examinee willfully submits to the evaluations. The consent should also be informed, meaning that the individual must understand the full implications of consenting to the test.
Other ethical issues include treating the examinee with dignity throughout the process and adhering to applicable data privacy laws while disseminating polygraph test results.
