One of the main issues arising in the context of polygraph examinations in general — and particularly in the area of labor relations and claims of violation of employees' legal and constitutional rights — is the issue of the validity and reliability of the polygraph device.
In the Tel Aviv University case, which serves as a leading precedent regarding employee suitability tests, it was determined that in order for an employer to be permitted to subject an employee or a job candidate to any form of examination, the test must be recognized as both reliable and valid.
Reliability It refers to the degree of consistency in measurement results obtained through repeated examinations. In other words, a testing method is considered reliable if and when repeated tests of the same subject yield similar results. A measurement is considered valid when it accurately reflects the characteristic it is intended to measure — that is, the degree of alignment between the measurement and what it is supposed to assess. In other words, it examines the extent to which the test fulfills its intended purpose.

A – Validity of the Polygraph Examination:

Since the investigation of employee misconduct has, at least on the surface, a nature that resembles incidents investigated in criminal inquiries, I will refer, for the purpose of discussing the validity of the polygraph examination, to general studies conducted on the subject, which examined the validity of the polygraph test using the Control Question Technique (CQT). There are two primary methods for assessing the validity of polygraph examinations: field studies and laboratory studies.

Field Studies are real-life cases of polygraph examinations. In these studies, the researcher compares the decisions made by the original polygraph examiner with the actual situation of the subject — whether they are innocent or guilty, their suitability for the role, etc. The actual situation can be verified based on legal outcomes, confessions, the subject's actual job performance, the transfer of material, and its review by a team of legal professionals who were asked to provide an expert opinion on the subject's involvement, and so on. In my opinion, it is very difficult to obtain accurate statistics regarding the validity of the polygraph examination through field studies.

This approach is also accepted by Eitan Elad (A. Elad, note 6, pp. 195-196, 7, 207), who argues that the Achilles' heel of field studies is the reliability of the criterion for guilt or innocence. The confession criterion, for example, is problematic, as false confessions are not uncommon and are sometimes obtained under the influence of polygraph test results. Even a court conviction, as a criterion for guilt or innocence, suffers from many errors.

However, as will be seen later, there is also reference to the validity of the examination based on the results obtained in field studies, and therefore I will also mention them.

Laboratory Studies attempt to replicate conditions that resemble real-life scenarios. The subjects are typically students who are aware that they are participating in an experiment and are compensated for their participation with payment or other benefits. In contrast, the population of subjects in real polygraph examinations is much more diverse (in terms of education, age, economic status, ethnic groups, etc.). The equipment used in laboratory conditions is generally more sophisticated, but the examiners typically lack formal training as polygraph examiners.

It must be taken into account that it is very difficult to reach accurate conclusions regarding the validity of the polygraph examination through laboratory studies, for two main reasons:

First, a person being tested in a polygraph examination must enter the appropriate psychological state for the test due to their feeling of being threatened by the procedure. If the subject's sympathetic nervous system does not activate, it is impossible to reach a true and accurate result in the test. When the test is conducted in a laboratory setting and the subject knows that they are not lying, or alternatively does not feel threatened by the questions — especially the control questions — their sympathetic nervous system will not activate. As a result, their physiological responses recorded on the polygraph chart will not reflect the facts of the case, and true conclusions cannot be drawn.

Secondly, the examiners in laboratory studies are usually inexperienced or untrained in conducting polygraph examinations under real conditions. As will be seen later, the examiner's role has a significant impact on the final results. Therefore, it is difficult to determine the validity of the examination in real-world scenarios when the conditions for conducting the study are completely different from those of an actual polygraph test.

The statistics presented by supporters of the Control Question Technique (CQT) method indicate that the success rate of the polygraph examination is very high. Raskin, for example, states that 95% of guilty subjects are identified as such in the examination, and 85% of innocent subjects are identified as innocent. Similarly, Dr. Berland, Raskin's research partner, believed that if the polygraph is operated correctly by a qualified examiner, the accuracy of the test results reaches between 80% and 95%. However, according to Berland, the results of the examination should be considered only as part of the overall body of evidence, and they should not be relied upon solely in court.

In reference to the body of field and laboratory studies, a pattern of relatively high validity can be found concerning guilty subjects. Most studies indicate that the level of validity is slightly lower when it comes to polygraph testing of innocent subjects.

By the way, for those who raise their eyebrows at the percentages mentioned and claim that, based on these, the tool is unreliable — it should be noted that these are very high percentages, especially when compared to the validity of ergometry tests conducted in hospitals (stress tests), which are only about 65%, and based on their results, life-saving medical treatment decisions are made.

It should be noted that the U.S. Congressional Office of Technology Assessment (OTA) report, which in 1983 reviewed dozens of studies regarding the validity of polygraph examinations, found significant evidence supporting the validity of polygraph tests in the field of criminal investigations.

There are, of course, several factors that can influence the accuracy of a polygraph examination. One of the main factors is the ability, at least theoretically, of a subject to attempt to interfere with the test and try to "fool the device." In professional terminology, these attempts to interfere are called COUNTERMEASURES, and the more experienced the polygraph examiner is, the better they are able to detect and handle them.

An experienced polygraph examiner is required to identify and address additional variable factors that may influence the physiological and psychological responses of the subject during the polygraph examination. The emotion of fear is essentially the fear of exposing the truth by the truthful subject and the fear of a falsehood by the truthful subject. Fear triggers the psychological mechanism that directs the subject's selective attention, focusing on the most immediate and significant threat. The examiner must diagnose and neutralize feelings of guilt that arise in the subject as a result of actions that contradict personal values, tradition, or upbringing, as well as internal conflicts that create perceptual imbalances. This includes a conflict between the desire to confess due to feelings of guilt and the instinct for self-preservation, false hope for the truth by the subject speaking falsehoods, and fear of falsehood by the subject telling the truth. Additionally, the examiner must be aware of feelings of guilt due to failed responsibility in the truthful speaker, anger at the forced situation, surprise at the embarrassing and humiliating situation, emotional arousal during the reconstruction of the crime and/or traumatic act, particularly in the case of a truthful subject being tested as a victim of crime (for example, a rape victim, etc.).

Additional variable factors that may disrupt the examination include: external or internal noise, changes in the positioning of the question on the chart, changes in the examiner's tone of voice, extreme responses on the first chart, extreme responses to the first question on the first chart, the first relevant question, the proximity question (SR), and changes in the blood pressure cuff pressure.

The examiner must be alert and aware of additional factors that should be assessed during the early interview stage (PRETEST) and the pre-examination conversation. They need to be cognizant of any expectations the subject may have, paying attention to emotional triggers that could activate the parasympathetic system, thereby interfering with sympathetic responses and disrupting the test. Such triggers include the presence of emotional distress or deep sorrow in the subject (such as in cases of family mourning, etc.).

There are medications that affect the increase or decrease of the subject’s responses and may therefore disrupt the examination. These include stimulants, depressants, and beta-blockers. The examiner must take into account that other factors such as a sense of responsibility, fear of social status damage, respiratory or heart conditions, involvement of attorneys in the examination, as well as hypnosis and biofeedback, may also impact the results of the test.