People are deceptive. It’s a fact. Chances are you can recall a recent incident where you told a lie. There could be several reasons for your transgression, regardless of the logic behind your decision.

Discerning truth from falsehoods is challenging, and in 1878, the Italian physiologist, Angelo Mosso, invented the plethysmograph. The device measured physiological reactions in people when questioned. The machine analyzed cardiovascular and respiratory responses to discern if they were telling the truth or being deceptive.

Over the following century, other scientists built on this technology, refining it to the lie detector systems we know today.

What is a polygraph?

The word ‘polygraph’ means ‘many writings.’ The device’s name refers to recording select physiological activities occurring in the body during questioning. A polygraph examiner may use conventional analog or digital instruments during the process.

The polygraph collects physiological data from physiological systems using electric sensors fitted to corrugated rubber tubes. The examiner places the pipes across the examinee’s abdomen and chest to record respiratory activity.

The two metal plates fitted to the fingers act as adhesive electrodes, recording perspiration activity, and a blood pressure cuff analyzes cardiovascular action. These are the basic instruments used in a polygraph test.

However, some practitioners may include finger plethysmographs to monitor blood volume in the fingertip or motion sensors to monitor general movement that interferes with the test data.

The typical polygraph examination includes a pre-test interview, chart collection phase, and analysis phase. The pre-test involves the polygraph examiner introducing the examinee to the parameters and specifics of the test.

The chart collection phase involves the examiner administering and collecting several polygraph charts. These questions vary depending on the questions, issues, and techniques used by the examiner. Following the chart collection phase, the examiner analyzes the charts to determine whether the examinee is truthful or deceptive in their answers.

Who Uses Polygraphs?

Four sectors use the polygraph, including the private sector, legal practitioners, law enforcement, and government agencies.

  • Private Sector

Corporations and companies execute polygraphs under the limitations and restrictions of the Employee Polygraph Protection Act of 1988. For instance, if you operate a cash business like a gold exchange, you might initiate a polygraph for new hires to ensure they don’t have drug problems, gambling addictions, or hidden agendas involving conducting criminal activity after their hiring.

  • Legal Community

The U.S. Attorney Offices, Public Defender, District Attorney Offices, Parole & Probation Departments, and defense attorneys utilize polygraphs. The court systems also use these tests in cooperation with parole and probation officers and psychotherapists to monitor sex offenders. Attorneys may also use the polygraph in civil litigation proceedings.

  • Law Enforcement Agencies

Federal, state, and local law enforcement agencies such as sheriffs and police departments. May use polygraphs when interrogating suspects.

  • Government Agencies

The Department of Defense and agencies like the CIA and FBI may use polygraphs when hiring staff or interrogating suspects.

The Top-Rated Polygraph Systems

Here are the top-rated polygraph systems available. If you’re looking to start a career as a polygraph examiner, you need the right equipment for the task. These systems are the benchmark in polygraphs. Let’s unpack each of them in detail.

Axciton Systems, Inc.

Axciton Systems, Inc. was the first organization to manufacture a digital computerized polygraph system. The company spent the last 25 years developing and advancing the technology, focusing on the science of polygraphs and how to integrate it with functional, accurate polygraph tech.

Axciton relies on the feedback it receives from polygraph examiners using its systems to continue to advance its science and systems. The company has a quick turnaround time for implementing new strategies in its polygraph tech, improving accuracy and efficiency in its range of polygraph products and software.

Axciton dedicates its resources to examiners, offering one of the best polygraph systems available, thanks to the tech constantly evolving and maturing over time. Axciton has a catalog of highly effective algorithms, such as the ‘White Standard’ and ‘White Devagus-Despike,’ which ensure polygraph examiners’ outstanding overall accuracy during the examination.

The company continues its research and development into the hardware and software systems involved in the polygraph examination process. Its tools enhance the scoring ability of the examiner while simplifying processes involved with the examination and data analysis.

Axciton Systems – Innovation

Axciton offers a comprehensive, versatile, and incredibly powerful software package designed for optimal results in the polygraph process. One of the issues facing examiners during the polygraph interview is detecting physical countermeasures, such as a tack in the shoe or clenching of the sphincter during answers.

Axciton Systems, Inc. introduced the advanced Motion Sensor Pad to eliminate these countermeasures during the examination process. This pad’s sensitivity is so refined that it detects even the slightest contractions and toe curls without needing additional attachments to the polygraph system.

The Motion Sensor Pad from Axciton is lightweight and easy to install and use. Axciton Systems, Inc. was also the first digital polygraph company to develop and release the piezoelectric pressure sensor technology relying on piezoelectric crystals to convert vibration to electrical impulses or vice versa.

The new and improved five-channel sensor box runs on the Windows-based software offered by the company. Axciton Systems, Inc. dedicates itself to advancing and developing cutting-edge polygraph systems and software, continuously implementing new features that meet the needs and requirements of examiners.

Axciton Systems – Hand Scoring Tools

The latest update to the Windows Software offered by Axciton introduces the ‘Hand Scoring Tool,’ showing the option of selecting a 3-point and 7-point scoring system. Examiners also have the choice of choosing the sequence of questions they want to score.

The Axciton Hand Scoring Tool provides a total score per question, calculating a total for all inquiries. At the end of the examination, the examiner can call for the selected spot and session. Unlike other hand-scoring tools, the examiner can resize windows to make them more visually appealing.

Axciton Systems – STAR

Examiners can also create unlimited hand-scoring tables for the examination session. However, the Axciton system excels with the development of hidden primary bimodal data populations from secondary bimodal populations using its STAR math algorithm.

At the core of polygraph scoring methodologies, we find how to combine scores from individual polygraph channels in a means that closely approaches a truthful state or correct deceptive within the mind of the polygraph subject.

Axciton defines this as ‘scoring accuracy’ in creating the deceptive bimodal/ hidden, unseen truthful population. The clarity, countermeasure controls, and the stability of emotional channels outside fear during the polygraph exam are separate from its scoring accuracy. Axciton published these findings in a different paper on the DRIFT concept.

This overview of the STAR algorithm concerns scoring accuracy alone and not with the DRIFT concerns, which Axciton uses for separate R&D directions.

STAR math is the product of the insights on polygraph tech and systems developed by Bruce White. Most of the data that’s required to create the hidden, unseen bimodal data population features in the relationship of separate convolutional systems. These systems come embedded in secondary bimodal data populations, such as electrodermal, pneumo, or cardiovascular data sets.

This specialist deconvolutional relational process method is proprietary to Axciton. Still, it forms the foundation of the exceptional scoring accuracy available for the STAR algorithm in the lab and the field on confirmed cases.

Regarding accuracy, the lab data from Axciton shows confirmed cases for NDI populations at 93% with no false hits in the population 336 Zone, MGQT, and 2QZone. It offers 92% accuracy for DI population 483 Zone, MGQT, and 2QZone.

DI confirmed populations did experience 2% false readings but didn’t have motion channels. These sessions may have experienced unconfirmed countermeasure oddities, such as heavy MI. Countermeasure attempts are greater in DI populations when compared with NDI populations. So, most STAR users already own a motion pad sensor to reduce the efficacy of these countermeasures by examinees.

Approximately 60% of this population includes four past APA presidents, q/c departments, and other professional leaders. There is no report of a confirmed non-DRIFT inaccuracy or false hit in the last five years. STAR has integrated into the use of Axciton motion pad STAR users.

The only drawback with STAR is its inability to know when it runs a bad examination. It expects clarity of issue from the examiner, effective countermeasure controls, and proper DODPI techniques and procedures on single-issue tests. With these methodologies in place, STAR achieves consistent accuracy that exceeds expectations.

While the STAR algorithm costs a hefty $2,500, it comes with unlimited free email processing for Axciton customers. STAR users may also process colleagues’ charts for free. Overall, Axciton offers one of the best polygraph systems available on the market, and it’s a top choice for examiners in any industry.

Lafayette Instrument

Lafayette Instrument is a leading brand in polygraph tech and possibly the biggest name in the industry. Max Wastl founded the company after he immigrated to the US, studying electrical engineering at Purdue University.

He established the Lafayette Instrument Company in 1947 after completing his degree. The company started in a small shed with a single employee. Lafayette started exploring polygraph technology, psychological testing, and physiological recording instrumentation.

Lafayette Instrument – Acquisitions

The ongoing company expansion drew international attention to the company. As a result, Lafayette acquired Campden Instruments in 1998, intending to make it a complement and extension to Lafayette’s product line.

In 2016, Lafayette saw a growing need in the market for science-based credibility assessment training. As a result, it launched the ‘PEAK Credibility Assessment Training Center.’ The project aimed to deliver world-class data measurement, analysis, and acquisition software and instrumentation to advance security, safety, and science.

Lafayette continues to innovate and refine its processes and products for its clients. The premium LX Software from the company offers a ground-breaking ESS-M Interpreter further to improve the scientific accuracy of its data interpretation.

The innovative ‘Respiration Line Excursion (RLE) Tool’ effectively measures the ratio of relevant biological and physiological responses divided by the comparison response to produce a recommended ‘pneumo score.’

Examiners can visually analyze and compare changes in pulse amplitudes with the PLE Pulse Amplitude Tool. The examiner gets a simple step-by-step process for generating paperless reports and charts. The innovative tech pairs seamlessly with the ‘Memory Ping’ functionality, offering fast and easy CIT testing and interviews.

The LX Software is accessible and available in GSR or GSC, with manual, automatic, and detrended modes. Users receive free downloads for life, bundled with OSS-3, PolyScore, and drug reference documentation.

The ‘Memory Ping’ permits investigators to conduct their testing on subjects to determine involvement in crimes under investigation. It achieves it by detecting information in the suspect’s memory during the examination.

The suspect experiences uncontrollable physiological reactions while detailing the crime. It picks up reactions that don’t occur in innocent individuals. Memory Ping allows examiners an easy pathway to finding out if the suspect knows the information.

Limestone Technologies

Lafayette Instrument acquired Limestone Technologies, making it a division of the company. Limestone Technologies is committed to continuous innovation of instrumentation solutions and software that contributes to securing and safeguarding the community.

Limestone Technologies was established in 2003, unveiling the Polygraph Pro Suite as its flagship product. The company quickly dominated the space of polygraph instrumentation and software, catching the attention of Lafayette.

Limestone promises examiners unmatched reliability, unparalleled performance, and unrivaled innovation. While the company focuses on providing instrumentation and software, in 2017, the company started to concentrate on polygraph training and education.

Before its acquisition by Lafayette, Limestone acquired the ‘Backster School of Lie Detection.’ As one of the oldest and most established polygraph schools, it provides world-class polygraphy training for polygraph examiners.

Lafayette Instrument Company acquired Limestone Technologies in August 2022, with the company president, Jennifer Rider, issuing the following statement on the purchase.

“We are very pleased to bring these two companies together to achieve our collective potential and maximum effectiveness and efficiency for the benefit of our customers.”

Limestone Technologies has its headquarters in Kingston, Ontario. It has a complete staff complement and operates independently of Lafayette. The company has sales and customer service to help examiners select the right equipment to match their requirements in the field.

Limestone Technologies Inc. is a reliable and trusted provider of specialist psychological and medical services, products, and solutions, focusing on public safety and security. The management remains committed to elevating the brand through commitment to quality, innovation, and world-class customer service.

The company continues to increase awareness of its data acquisition solutions and grow its reach in the market. It relies on open-minded communication with its clients, producing a mutually beneficial synergy between the company and its clients and increase customer loyalty.

Limestone Technologies – A History

It’s a respected company in polygraph credibility assessments and sex offender management. The company specializes in bringing expertise and knowledge to customized solutions for biofeedback instrumentation. Limestone Technologies prides itself on creating a close relationship with its clients, using feedback to refine and develop its software and systems.

Limestone Technologies Inc. provided two security and public safety data acquisition solutions in 1999. Limestone has a reputation in the market as a leader in excellence and innovation. They’re known for quality polygraph phallometric solutions and eager to apply their attention and experience to other similar technologies.

The company delivers medical-grade instrumentation with intelligent software design, bringing a selection of sub-markets with similar requirements. Limestone introduced its ‘Polygraph Pro Suite Products’ in 2003, developing its systems and software in collaboration with its examiners.

The Polygraph Pro Suite delivers a user-friendly software interface and exceptional chart quality that is the industry’s benchmark. The ParagonX Acquisition System is possibly the most powerful polygraph data acquisition system available on the market. These instruments go above and beyond leading polygraph systems offered by other manufacturing brands to dominate the field of polygraphs.

Examiners have a choice of high retention USB to dual channel 32 bit, delivering performance and reliability with the high retention USB. ParagonX utilizes the High Retention USB system, providing a 7.5X increase in data transfer rates and a 20X increase in bandwidth.

Limestone Technologies – ParagonX Software

The ParagonX software offers industry-leading sampling rates, 625 samples per second per channel. These specs make it the highest sampling rate in polygraph instrumentation. Polygraph examiners need equipment they can trust to make accurate and informed assessments without overlooking or compromising performance, precision, and design.

ParagonX is the first upgrade to its best-selling polygraph system. The project engineers work behind the scenes, enhancing the software to create the most intuitive and powerful acquisition system on the market.

Limestone Technologies offers a trade-in program for examiners. They can exchange their original Paragon, DataPac, or if they want to switch from competitors’ instruments. With this program, examiners can save up to a $2,700 discount on the new equipment and software.

Limestone Technologies offers a very expensive solution, but it’s a world-class system and software designed for professionals that demand the best.


Stoelting is another leading brand in polygraph technology. It’s one of the oldest companies in the space, founded as ‘Chicago Laboratory Supply and Scale Company’ in 1886. Today, it’s undergone a name change, but it still produces some of the highest-quality polygraph technology in the industry.

Stoelting Co. has four separate divisions, making it a highly diversified company. The core product lines are physiological, psychophysiological, and psychological measurements—the inter-relationship structure of its offering results in exceptional synergy and ideas across the company.

Breakthroughs in one division usually end up in applications in other company divisions. This dynamic environment is central to Stoelting’s growth over the last century of its operations. Christian Hans Stoelting was a pioneer in psychological and physiological apparatus development.

Stoelting – A History

Stoelting built the company into one of the most respected organizations in the scientific community, cementing its reputation as a top player in the space. Stoelting founded the company in 1903, making it one of the oldest players in the polygraph industry. From 1903 to 1943, it was a dominant force in American psychology.

At the St. Louis Universal Exposition in 1904, Stoelting Co. received medals for ‘Anthropometric Apparatus and Psychometric Apparatus.’ The company started with humble beginnings on the west side of Chicago, moving to its modernized headquarters in Wood Dale, Illinois.

Stoelting maintained its tradition of manufacturing and distributing superior polygraph instruments worldwide. Stoelting’s Polygraph Division is a pioneer in the polygraph field, with many other companies imitating its advancements.

Stoelting – Developing Polygraph Technology

In 1935, Stoelting was the first to create the Cardio-Pneumo Polygraph, and it stayed at the cutting edge of technology, providing the highest caliber instruments. The middle of the twentieth century brought many advancements for the Stoelting range of polygraph technologies.

Stoelting is the top-tier choice for prominent polygraph schools and examiners. The company introduced the Reid polygraph in 1951, a five-channel model that recorded signals from respiration, arm movements, blood pressure, GSR, and leg movements.

In 1958 Stoelting debuted the ‘Deceptograph,’ with the US Military standardizing the technology throughout the armed forces. In 1966 Stoelting designed and developed the non-battery powered galvanometer polygraphy. In 1974, Stoelting debuted the first all-electronic polygraph system.

In 1978 The Stoelting Ultrascribe debuted, becoming the company’s most successful system. Its modular design allows for three to five channels, giving the examiner more freedom to choose how many channels they want to implement, along with inexpensive upgrades that are easy to implement.

In 1982, Stoelting released the ‘Executive Ultrascribe.’ It was more compact than its predecessor and lighter. The improvements in the device’s form factor made it become the US military’s official polygraph system. The Ultrascribe II was released in 1983, featuring the first-ever polygraph with microprocessor-controlled re-centering.

As computer-assisted polygraphy technology took off in the late 1980s, Stoelting launched its Computerized Polygraph System in 1992, entering the digital age of polygraph tech. This shift brought about superior flexibility and accuracy to the polygraph.

Today, Stoelting’s CPSpro is the benchmark standard of computerized polygraph tech. It implements cutting-edge algorithms, amazing accuracy, and user-friendly features, making it one of the best systems in this review.

Examiners can depend on Stoelting’s polygraph systems for high-quality, reliable polygraph instruments and excellent user support from its team of knowledgeable and educated customer service specialists. It’s a top choice for examiners and one of the leading companies in polygraph systems.

Next: How to become a Polygraph Examiner