A great deal of development has taken place in the realm of investigations, much to the advantage of seekers of truth. In this day and age, it is difficult for perpetrators of crimes to get away that loose due to the array of equipment used by investigators. Polygraphs are a great technological tool that is commonly used by private investigator agencies in uncovering the truth and presenting it to their clients.

However, a common issue that keeps arising with regards to the technology is how accurate it is. For instance, its proponents have rated it as 95-98% accurate while critics have given it an accuracy level of as low as 65% accuracy. With this in mind, you should take note of the fact that most of this debate is centered on perception and not concrete data as research into matters of polygraphs are usually not easily found in the public domain.

But still when it is compared to other forms of truth-seeking tools such as questionnaires, inquiries and interviews, polygraph are substantially more accurate and better with regards to seeking out the truth.


So What Makes Polygraphs So Accurate?

As a matter of fact, humans have psychological reactions whenever they answer a question during interactions, which are manifested in various physical elements of their body. This is the basis of polygraphs. Polygraphs tap into these reactions to indicate whether or not someone is lying. By measuring changes in temperature, breathing rhythms, blood pressure, sweating amongst other things, the private investigator is able to recognise instances where a lie has been told. Since it is difficult to constantly control all these elements at a go, it becomes inherently difficult to cheat on a polygraph.


Administering A Polygraph

Administering a polygraph should be a preserve of a trained and expert private detective. During the examination, the examiner follows a standard procedure that entails a pre-test phase, where the examinee is prepared to take the test, a chart collection phase and finally the test data analysis.

The pre-test phase also entails a phase determining whether the examinee is capable of taking the test. With this in mind, the private investigator asks control questions to establish a standard measure of truthful and false responses. This establishes the base level of the vitals that are being measured as well as helps to distinguish between test anxiety-based spikes in vital signs and lying anxiety spikes.

The chart phase is where the examiner asks the questions that are related to the investigations that private investigators are concerned with. The third phase is concerned with analysing the recorded data which may take place in tandem with the second phase or may be carried out afterwards.

As a pointer to confidence in its accuracy, polygraphs are used in several parts of the UK to determine the eligibility of sex offenders to be released from jail. This shows just how reliable polygraphs are perceived to be.