Polygraphing and its application in the Conventional Investigative Process can be a contentious issue. There are many reasons for this, but ultimately, as in all things, the level of input is equivalent to the resultant product.

The bulk of research done over the years, irrespective of personal opinion, is indicative of the fact that properly conducted polygraph examinations produce findings significantly better than chance.

As such, this investigative tool has significant potential in the conventional investigative field.

Where did polygraphing come from?

The detection of lies – and the importance of truth – has long been valued and sought in decision-making processes. Inarguably, with elevated knowledge and insight, we have the ability to make improved decisions, irrespective of circumstance.

In 220 BC, Chinese subjects who were under investigation were made to chew on rice for a period of time, then spit it out. If the chewed rice was hot and lumpy, the subject was deemed truthful. If it came out dry, he was considered deceitful. This simple yet effective physiological response to threat was one of the first known starting points in the pursuit of truth, using means other than the spoken word.

Today, although methodologies and technologies are much improved, the ability of the investigator to reduce the scope of any given pool of potential suspects remains key in any investigative process. This is where professionally administered polygraph testing can be of great value, offering the most accurate means of differentiating truth from lies in the world today.

What is the polygraph?

It is not a “lie detector,” but rather an instrument that is used to measure physiological changes in relation to a stimulus or question. A good comparison may be the use of a thermometer to measure temperature changes.

In this case involuntary physiologically activity, as well as intentional, disruptive physical activity (physical attempts at countermeasures) are recorded and analysed, using various components, which are mostly attached to the subject.

How do I choose my polygraph examiner?

The most critical aspect of the entire examination is the examiner. The following is a list of “musts” which should be complied with, failing which the examiner should not be engaged:

  • International accreditation/qualification
  • Not exceeding the maximum number of four tests per day
  • Proper test durations of 90 minutes per exam
  • Willingness to have his/her work reviewed, to confirm outcome and/or quality
  • Proper technology, including uninterrupted recordings, of the entire process and anti-countermeasure sensors

Is polygraphing admissible?

The only test in terms of the admissibility of any form of evidence is in terms of its relevance.

It follows that if the evidence gathered during the course of any given polygraph examination, relates to the issue under scrutiny, should therefore be admissible.

This evidence, then, has to be heard and the value thereof tested. To refuse polygraph evidence without reason, could flaw the process (See: Truworths Ltd v CCMA & others (2008) 17 LC 1. 11. 73).

Reported in (Butterworth’s)

[2008] JOL 22565 (LC) 1 August 2008.

Can I use the result at the CCMA?

The evidence of polygraph examiners is being accepted by the CCMA on a daily basis. It remains, however, the duty of the commissioner to determine the admissibility, reliability and relevance of all evidence which is presented.

Polygraph test results on their own are not an automatic basis for a finding of guilt, but can most certainly be used in support of other evidence. This is true in respect of most other forms of forensic evidence, even such evidence as latent fingerprints, for example, the importance and relevance of which also need to be quantified in terms of the investigation as a whole.

How do I know the difference between a good and bad examiner?

Good examiners will apply the following:

  • International standards of ethical practice
  • Application of polygraph within the ambit of an investigative process
  • Decision-making on evidence gathered and primarily focused on such
  • Being open to scrutiny and being accountable
  • Fully recorded interviews

Bad Examiners will display the following tendencies:

  • No interest in being governed in terms of accepted standards
  • Not being transparent in so far as work product
  • Not being focused on examination resolution
  • Not being adequately trained/equipped to operate within an investigative field

What are the techniques used and are there any shortfalls?

There are many different techniques and technologies out there and a good polygraph examiner will be able to administer various types of tests, depending on the specific requirement at hand.

Polygraph testing is not to be confused with any form of voice stress analysis. To further educate yourself as to the aforementioned process, the following link can be watched:

VSA: http://www.youtube.com/watch?v=Rr3E_2KTxI0

Here are three interesting case studies:

  • In Govender and Chetty and Cargo & Container Services KN4881, the Commissioner said that the failure of the two employees in two polygraph tests lends some support to the finding of the facts that they were involved in theft.
  • In Hotellica Trade Union and San Angelo Spur WE3799, the Commissioner found that although refusal to take a lie detector test may not be interpreted as implying guilt, it can be regarded as an aggravating factor, especially where there is other evidence of misconduct.
  • In CWIU and Druggist Distributors WE10734, the Commissioner said that it is not necessary to deal with the weight that should be attached to the polygraph test if the company did not rely on the test to establish the employee’s guilt, but regarded it merely as additional evidence that would demonstrate whether the employee’s version was truthful, and provided an opportunity for the employee to disprove the company’s evidence

Does polygraphing really work?

We have documented, over multiple years using various examiners, an average resolution rate in the region of 90% of all matters undertaken, using polygraph testing as it should be applied. It is, however, very important to reiterate that the aforementioned process is only as good as the examiner. If the required standards are not met and the correct protocols not followed, the entire polygraph examination will be irreversibly flawed and the investigation possibly misdirected.

It is also important to remember that the polygraph should be utilized as an effective investigative tool, rather than as a comprehensive solution to any given situation.

As in all investigative matters, the ability to resolve failed tests is critical, as merely having the ability to issue pass or fail examinations outcomes will seldom achieve any intended investigative goal.


This article was written by Gillian Bolton, and is courtesy of our partner, Moore Stephens: http://southafrica.moorestephens.com/

You can download the original article here.