Employers are often faced with misconduct or criminal activities such as misappropriation of property or theft in its work environment, without knowing exactly where, how and by whom it is committed. It is crippling the business and the employer is at its wits-end how to find the culprits! To make things worse, you suspect that there are accomplices amongst your employees, sharing in the illegal proceeds and helping to hide the crime!

Why do critics figures vary?

One of the problems in discussing accuracy figures and the differences between the statistics quoted by proponents and opponents of the polygraph technique is the way that the figures are calculated. At the risk of over simplification, critics, who often don't understand polygraph testing, classify inconclusive test results as errors. In the real life setting an inconclusive result simply means that the examiner is unable to render a definite diagnosis. In such cases a second examination is usually conducted at a later date.

To illustrate how the inclusion of inconclusive test results can distort accuracy figures, consider the following example: If 10 polygraph examinations are administered and the examiner is correct in 7 decisions, wrong in 1 and has 2 inconclusive test results, we calculate the accuracy rate as 87.5% (8 definitive results, 7 of which were correct.) Critics of the polygraph technique would calculate the accuracy rate in this example as 70%, (10 examinations with 7 correct decisions.) Since those who use polygraph testing do not consider inconclusive test results as negative, and do not hold them against the examinee, to consider them as errors is clearly misleading and certainly skews the figures.

Voice stress analysis

Voice stress analysis (VSA) refers to the use of devices that purportedly detect the existence of truth, deception, and/or stress from voice and speech. Manufacturers of VSA devices note that their low cost, short training and high accuracy render the VSA an invaluable tool for law enforcement and military personnel.

However, substantiation of VSA's utility proided by these companies has consisted of only single-case ecamples and/or anecdotes without any scientific evidence regarding their efficacy. Research regarding the accuracy and efficacy of VSA has, to date, been mixed at best.

Although some studies have shown VSA technologies to be sensitive to stress, none of the studies found these technologies to provide reliable indicators of deception or truthfulness.

What is Polygraph ?

The term "polygraph" literally means "many writings." The name refers to the manner in which selected physiological activities are simultaneously recorded. Polygraph examiners may use conventional instruments, sometimes referred to as analog instruments, or computerized polygraph instruments. It is important to understand what a polygraph examination entails. A polygraph instrument will collect physiological data from at least three systems in the human body. Convoluted rubber tubes that are placed over the examinee's chest and abdominal area will record respiratory activity.

Two small metal plates, attached to the fingers, will record sweat gland activity, and a blood pressure cuff, or similar device will record cardiovascular activity. A typical polygraph examination will include a period referred to as a pre-test, a chart collection phase and a test data analysis phase. In the pre-test, the polygraph examiner will complete required paperwork and talk with the examinee about the test. During this period, the examiner will discuss the questions to be asked and familiarize the examinee with the testing procedure.

During the chart collection phase, the examiner will administer and collect a number of polygraph charts. Following this, the examiner will analyze the charts and render an opinion as to the truthfulness of the person taking the test. The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to one or more questions asked during the test. It is important to note that a polygraph does not include the analysis of physiology associated with the voice. Instruments that claim to record voice stress are not polygraphs and have not been shown to have scientific support

Polygraph

The polygraph is the only lie detection technique that has proven, independent, scientific, reliability and validity studies and peer acceptance; it is the only lie detection technique directly used by government agencies and private institutions worldwide for investigatory purposes; and, it is used by more state and local law enforcement agencies than any other truth verification technique available

PROCEDURES FOLLOWED DURING AN EXAMINATION

A typical polygraph examination will include periods referred to as a pre-test phase, a chart collection phase, post-test phase and a test analysis phase. This procedure usually takes one to one and a half hours.
In the pre-test phase, the polygraph examiner will complete required paperwork and explain the theory of the polygraph in an understandable way to the examinee. The examinee will be given the opportunity to discuss their roles or perceptions regarding the case under investigation and provide relevant information. During this period, the examiner will discuss the questions to be asked and familiarise the examinee with the testing procedure.
During the chart collection phase, the examiner will administer the examination and collect a number of polygraph charts. No questions will be asked during the examination that have not been discussed and reviewed with the examinee.
In the post-test phase, the examiner will analyse the charts and render an opinion as to the truthfulness of the person taking the test. The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to any questions asked during the examination