Can You Fail A Polygraph Even If You Are Telling The Truth?

If someone is considering arranging a lie detector test or is due to take the test themselves, it’s natural to have plenty of questions about how the process works. 

When polygraph testing is carried out by a reputable firm such as Reveal PI, there is a rigorous framework in place to ensure the utmost level of accuracy and professionalism. The test is also carried out in accordance with data protection laws. 

However, during the test, the participant may wonder whether there is a possibility that even if the truth is told, the readings may give a different answer. 

To alleviate any concerns about the accuracy of lie detector testing, here is more information about how polygraph tests work, including how the test has been designed to weigh up several variables to reach the conclusions given. 

What Is A Polygraph Test?

A polygraph test (also known as a lie detector test) measures various physiological responses produced by the body to help determine whether or not someone is telling the truth or not while being asked a series of questions. 

Polygraph testing was originally invented in 1921, although in the 1980s, inventor Bruce White developed the first fully computerised polygraph that more closely resembles the testing setup used today. 

Refinements continue to be made to lie detector testing equipment and software so that the service benefits from the latest technological advancements.   

The physiological responses that a polygraph test can measure and interpret includes:

• Blood pressure
• Breathing rate
• Sweat rate (galvanic skin response)

Modern polygraphs generate so much data that computer algorithms are needed to process and interpret the results. Information is shown on a screen displaying any fluctuations in the rhythms which could indicate a particular response. 

What Can Polygraph Testing Be Used For?

Most commonly, polygraph tests are associated with infidelity lie detector tests. However, polygraph testing can be used for a vast range of personal or corporate purposes.

While far from exhaustive, reasons why an individual or company may want to arrange a lie detector test include:

• Background checks
• Fraud investigations
• Infidelity
• Theft
• Someone wishing to prove their own innocence 

How Are They Carried Out?

At Reveal PI, lie detector tests are carried out either in someone’s home or at a testing centre by one of our private investigators located in Birmingham.

To gather the data for the physiological responses, the examinee will be connected to the machine via a series of sensors. These sensors will then produce readings which the person conducting the test will be privy to, so that the truthfulness of the verbal answers given can be determined. 

Polygraph tests begin with a series of control questions to demonstrate what will be involved for the examinee. These initial responses also help guide the person conducting the test on how questions are answered by that individual. 

The actuall test will then begin and the the examiner will use the base readings to gauge reactions to the questions of concern. Instant results are given to promote a swift resolution to the enquiry. 

At Reveal PI, physical or digital results of our lie detector tests can also be provided. 

How Accurate Is A Lie Detector Test?

‘How accurate are lie detector tests?’, is a common question people ask when considering booking a test. 

On the whole, lie detector tests are considered to be highly accurate, due to the ability to analyse specific physiological responses as we’ve discussed above. That said, as with many testing types there is no guarantee of 100% accuracy. 

However, something that is worth bearing in mind is that due to the long history of lie detector testing, this does signify a healthy association of assisting with investigations. In addition, polygraph testing technology continues to improve, with enhanced data making it less likely for errors to occur. 

Can You Fail A Polygraph Even If You Are Telling The Truth?

People also want to know ‘how accurate are polygraph tests for infidelity?’

Regardless of the investigation type, it’s good to be aware that while false readings can never be fully ruled out, on the whole, lie detector testing is considered to be extremely accurate. 

There are some instances that can make it more likely the wrong result will be given. Though, one of the purposes of the control stage of the test is actually to identify such signs. These can include someone’s answering style or their general behaviour. 

Limitations Of A Lie Detector Test

Not a substitute for a full investigation – Depending on the matter being looked into, a lie detector test may offer insufficient answers. As answers are designed to be minimal rather than provide detailed information, additional investigative services may be needed. 

Results dependent on examiner competency – Reveal PI only work with members of the British Polygraph Society (BPS) and the American Polygraph Association (APA). As private detectives operating in Birmingham and across the UK, we are highly competent in all aspects of lie detector testing. If searching for lie detector testing elsewhere, the same level of quality assurance cannot be guaranteed. 

Requires user participation – Polygraph tests require the willing participation of the person that needs to be questioned. This may not always be the most suitable form of information gathering, depending on the investigation. For instance, covert surveillance may be more appropriate in cases where someone doesn’t want to let the other person know they are being investigated. 

Reveal PI – Lie Detector Test Birmingham

In search of lie detector testing in Birmingham?

Offering a highly professional service with instant results, Reveal PI is a leading private investigation firm. We offer lie detector testing (polygraph testing) alongside many other services to help provide answers to various personal and corporate investigation types. 
To book your private polygraph test in Birmingham please fill out our contact form or give us a call on 0121 663 0251 to speak to a member of our team.