Polygraph Manufacturers: The Complete Guide (2026)

Overview of the Polygraph Equipment Market

Every polygraph instrument used in professional credibility assessment today comes from one of four manufacturers: Lafayette Instrument Company, Stoelting Co., Axciton Systems, and Limestone Technologies (now a division of Lafayette). Each offers fully digital systems with computerised data acquisition, proprietary software, and scientifically validated scoring algorithms.

In the hands of a qualified and experienced examiner, all major polygraph instruments produce reliable results. The choice between systems often comes down to testing context, agency compliance requirements, scoring algorithm preferences, and software ecosystem. This guide provides a comprehensive, side-by-side comparison to help you make the right decision for your practice.

For a deeper understanding of how these instruments are used in the field, see our guide on how to analyze polygraph data according to APA standards.

History and Market Position

Lafayette Instrument Company is the world's leading manufacturer of polygraph instrumentation and equipment, serving private examiners, government agencies, and military organisations worldwide. Founded in 1947 by Max Wastl — a German immigrant who studied Electrical Engineering at Purdue University — the company began with a single employee and a small shed in Lafayette, Indiana [1]Verified Our Story — Lafayette Instrument Company
Confirms Max Wastl founded Lafayette Instrument Company in 1947, the 2016 founding of PEAK, and the 2022 acquisition of Limestone Technologies.. What started as a modest engineering venture focused on psychology instruments has evolved into the global leader in credibility assessment technology, with products used in over 100 countries [2]Verified Lafayette Instrument — Lafayette Life Science
Confirms Lafayette's founding by Max Wastl in 1947 and products used in over 100 countries..

In August 2022, Lafayette acquired Canadian manufacturer Limestone Technologies, bringing together two of the most trusted brands in polygraphy under a single company [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility.. Lafayette also operates the PEAK Credibility Assessment Training Center, an APA-accredited and AAPP-recognised polygraph training programme now based in Lakeland, Florida, which was founded in 2016 [6]Verified About PEAK — PEAK Credibility Assessment Training Center
Confirms PEAK was founded in 2016 by Ben Blalock with Lafayette Instrument, is APA-accredited and AAPP-recognised, now located in Lakeland, FL.. PEAK has trained nearly 300 polygraph examiners through its basic course and provided advanced training to over 1,000 examiners worldwide [6]Verified About PEAK — PEAK Credibility Assessment Training Center
Confirms PEAK was founded in 2016 by Ben Blalock with Lafayette Instrument, is APA-accredited and AAPP-recognised, now located in Lakeland, FL..

All our examiners at Lie Detector Test use Lafayette or Limestone systems across our 140+ testing locations.

Flagship LX6 Polygraph System

The LX6 is Lafayette's flagship system, offering 10-channel digital data acquisition with a data transfer rate of up to 360 samples per second across all channels and 32-bit analog-to-digital conversion [7]Verified Our Story — Polygraph by Lafayette Instrument Company
Confirms LX6 specifications: 10 channels, 360 samples/sec, 32-bit A/D conversion, Fischer quick-release connectors.. Key features include Fischer quick-release input connectors, medical-grade safety isolation, a rugged textured enclosure, selectable GSR/GSC channel, a dedicated PPG (plethysmograph) channel, dedicated seat sensor, and three additional auxiliary channels [7]Verified Our Story — Polygraph by Lafayette Instrument Company
Confirms LX6 specifications: 10 channels, 360 samples/sec, 32-bit A/D conversion, Fischer quick-release connectors..

The LX6 is compatible with both LXSoftware and the next-generation LXEdge platform, offering examiners flexibility in their software ecosystem. It represents the culmination of Lafayette's product evolution from the LX2000 through the LX4000 and LX5000 series.

ParagonX Pro (Limestone Division)

Following the 2022 acquisition, the Limestone ParagonX continues as a fully supported product within the Lafayette family. The ParagonX is a 9-channel high-resolution system featuring Lemo precision connectors, an integrated PPG channel, movement monitoring, and dual-channel 32-bit data acquisition [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility.. At a native 625 samples per second per channel, the ParagonX has the highest sampling rate in any polygraph instrument [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility., offering exceptional signal granularity for forensic-grade physiological analysis.

The ParagonX uses optical isolation greater than 5000 mV and is compatible with both the Polygraph Pro Suite software and Lafayette's LXEdge platform [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility.. It is particularly well-suited for PCSOT (Post-Conviction Sex Offender Testing) programmes, clinical settings, and high-volume monitoring environments.

History and Legacy

Stoelting Co. is one of the most historically significant names in polygraph manufacturing. The company traces its origins to 1886, when Christian Hans Stoelting — a German immigrant — established the Chicago Laboratory Supply and Scale Company [8]Verified Our Company — Stoelting Co.
Confirms Stoelting was founded in 1886 as Chicago Laboratory Supply and Scale Company by Christian Hans Stoelting, and details the company's polygraph history.. From 1903 to 1943, Stoelting was nearly unchallenged as the principal provider of scientific apparatus for American psychology [8]Verified Our Company — Stoelting Co.
Confirms Stoelting was founded in 1886 as Chicago Laboratory Supply and Scale Company by Christian Hans Stoelting, and details the company's polygraph history..

Stoelting created their first cardio-pneumo polygraph in 1935 [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978., entering the polygraph field that would become one of its most important divisions. In 1951, the Reid Polygraph was introduced, and in 1958, the Stoelting Deceptograph was standardised by the US military [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978.. A landmark came in 1974 when Stoelting released the Polyscribe — the world's first all-electronic polygraph [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978. — followed by the Ultrascribe in 1978 [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978.. Today, Stoelting is headquartered in Wood Dale, Illinois, and operates across five specialised divisions [8]Verified Our Company — Stoelting Co.
Confirms Stoelting was founded in 1886 as Chicago Laboratory Supply and Scale Company by Christian Hans Stoelting, and details the company's polygraph history..

CPS Elite Series and CPSpro Fusion Software

The CPS Elite Series represents Stoelting's current-generation hardware, featuring an 8-channel data acquisition system with a built-in touchscreen display, a touchscreen alert system for enhanced countermeasure detection awareness, Devagus motion artifact filters, and seamless integration with CPSpro Fusion software.

CPSpro Fusion is widely regarded as one of the most complete polygraph software platforms available. It features a dynamic question editor, advanced chart recorder, multimedia stimulus support, customisable question templates, secure chart archiving, and the scientifically validated CPS scoring algorithm — originally developed from research at the University of Utah [4]Verified Appendix F: Computerized Scoring of Polygraph Data — National Academies
Confirms CPS was developed by Scientific Assessment Technologies based on Kircher and Raskin research at the University of Utah, and PolyScore was developed at JHU-APL.. CPSpro Fusion also accepts imported data from Axciton, Lafayette, and Limestone systems via pREFORMAT, making it a versatile choice for cross-platform analysis.

Stoelting systems are particularly popular in polygraph training academies, military security units, and state law enforcement agencies, valued for their durable hardware design and intuitive interface.

Pioneer of Computerised Polygraph Testing

Axciton Systems holds a pivotal place in polygraph history. In 1990, the first commercially viable computerised polygraph system — both software and hardware — came from the Axciton Corporation in Houston, Texas [10]Verified Polygraph Test — ScienceDirect Topics
Confirms in 1990 the first commercially viable computerised polygraph came from Axciton Corporation in Houston; Raskin and Kircher developed a system about 2 years earlier.. About two years earlier, David Raskin and John Kircher at the University of Utah had developed a system consisting of a device that measured charts from an analog instrument, but Axciton was the first to produce a standalone commercial digital system [10]Verified Polygraph Test — ScienceDirect Topics
Confirms in 1990 the first commercially viable computerised polygraph came from Axciton Corporation in Houston; Raskin and Kircher developed a system about 2 years earlier..

Axciton's proprietary STAR (Statistical Test Analysis Report) algorithm and Motion Sensor Pad technology offer industry-leading resistance to physical countermeasures, making their systems particularly suited for controlled single-issue testing environments and counterintelligence applications. The WhiteStar scoring system provides additional automated analysis unique to Axciton hardware.

Hardware and Software

Axciton manufactures an 8-channel digital data acquisition system with an integrated Motion Sensor Pad for countermeasure detection. The system is designed for accurate data collection in government, law enforcement, and private practice settings, and is known for reliable hardware and countermeasure-focused engineering.

Axciton's proprietary software suite features an embedded operating system and the STAR algorithm for statistical pre-screening alongside examiner-led scoring. Data can be exported in pREFORMAT for cross-platform analysis in CPSpro Fusion or other scoring systems. Axciton instruments are widely used by government agencies and law enforcement examiners who prioritise countermeasure detection capability.

For examiners interested in the broader context of polygraph science, our scientific studies guide provides an overview of research methodologies.

High-Resolution Waveform Specialists

Limestone Technologies built its reputation on delivering the highest-resolution polygraph systems in the industry. The ParagonX system achieves a native 625 samples per second per channel — confirmed by the manufacturer as the highest sampling rate in any polygraph instrument [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility.. The system uses Lemo precision connectors and dual-channel 32-bit data acquisition with optical isolation greater than 5000 mV [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility..

Limestone was acquired by Lafayette Instrument Company in August 2022 [11]Verified Limestone Technologies — Welcome Page
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022., bringing together two of the most respected brands in polygraphy. The ParagonX system continues as a fully supported product line within the Lafayette family, and Limestone's ESS-M scoring algorithm is now integrated across both platforms.

Polygraph Pro Suite Software

The Polygraph Pro Suite is a feature-rich platform designed for Limestone Technologies series polygraph systems [12]Verified Polygraph Pro Suite Software — Limestone Technologies
Confirms Polygraph Pro Suite software features, ChartSync utility, and Limestone as a subsidiary of Lafayette.. It offers a user-friendly design with an easy-to-navigate front-end management system, integrated session management, online medical dictionary, automatic EDA modes (GSR/GSC switching), ReportBuilder+ for efficient report generation, text-to-speech question delivery, and an integrated ESS-M scoring interpreter.

The software includes ChartSync — a utility Limestone pioneered that synchronises video, audio, and chart data for comprehensive post-test review [12]Verified Polygraph Pro Suite Software — Limestone Technologies
Confirms Polygraph Pro Suite software features, ChartSync utility, and Limestone as a subsidiary of Lafayette.. It is now also compatible with Lafayette's LXEdge platform following the 2022 acquisition. For Canadian examiners exploring the profession, see our guide on how to become a polygraph examiner in Canada.

Key Specifications Compared

The following comparison covers the critical specifications across all four major polygraph systems:

Data Channels: Lafayette LX6 leads with 10 channels, followed by Limestone ParagonX with 9, and both Stoelting CPS Elite and Axciton with 8 channels each.

Max Sample Rate: The Limestone ParagonX achieves 625 samples/sec/channel — the highest in the industry [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility.. The Lafayette LX6 offers 360 samples/sec across all channels [7]Verified Our Story — Polygraph by Lafayette Instrument Company
Confirms LX6 specifications: 10 channels, 360 samples/sec, 32-bit A/D conversion, Fischer quick-release connectors.. Stoelting and Axciton systems operate at approximately 300 samples/sec.

A/D Conversion: Lafayette LX6 and the ParagonX both feature 32-bit analog-to-digital conversion [7]Verified Our Story — Polygraph by Lafayette Instrument Company
Confirms LX6 specifications: 10 channels, 360 samples/sec, 32-bit A/D conversion, Fischer quick-release connectors. [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility.. Stoelting and Axciton use 24-bit conversion.

PPG Channel: Both the LX6 and ParagonX include dedicated plethysmograph channels. Stoelting and Axciton offer optional PPG.

Activity Sensors: Lafayette provides seat and feet sensors. Stoelting includes a motion pad. Axciton features its proprietary Motion Sensor Pad. The ParagonX has integrated movement monitoring.

Built-in Display: Only the Stoelting CPS Elite features a built-in touchscreen display.

Connectors: Lafayette uses Fischer quick-release connectors. The ParagonX uses Lemo precision connectors. Stoelting and Axciton use standard connectors.

Primary Software: LXSoftware/LXEdge (Lafayette), CPSpro Fusion (Stoelting), Axciton Suite (Axciton), Polygraph Pro Suite (Limestone).

Scoring Algorithms: Lafayette supports OSS-3, ESS-M, and PolyScore. Stoelting supports CPS and PolyScore. Axciton runs STAR and WhiteStar. Limestone supports ESS-M and OSS-3.

Best For: Lafayette — federal, law enforcement, and private practice. Stoelting — training, military, and law enforcement. Axciton — counterintelligence, single-issue, and government. Limestone — PCSOT, clinical, and high-volume testing.

APA and ASTM Compliance Requirements

Every polygraph instrument used for professional examinations must include specific sensor components to meet the standards set by the American Polygraph Association (APA) and ASTM International. ASTM Committee E52 on Forensic Psychophysiology has developed comprehensive standards covering all aspects of polygraphy, including ASTM E2439 — the Standard Guide for Instrumentation, Sensors and Operating Software Used in Forensic PDD Examinations [13]Verified ASTM E2439 — Standard Guide for Instrumentation, Sensors and Operating Software Used in PDD Examinations
Confirms ASTM standards covering minimum requirements for polygraph instrumentation including simultaneous recording of respiratory, electrodermal, and cardiovascular activity.. ASTM E2063 covers calibration and functionality checks for polygraph instrumentation [14]Verified ASTM E2063 — Standard Practice for Calibration and Functionality Checks Used in PDD Examinations
Confirms ASTM calibration and functionality check standards for polygraph instrumentation..

As a minimum, polygraph instrumentation shall simultaneously record an individual's respiratory, electrodermal, and cardiovascular activity [13]Verified ASTM E2439 — Standard Guide for Instrumentation, Sensors and Operating Software Used in PDD Examinations
Confirms ASTM standards covering minimum requirements for polygraph instrumentation including simultaneous recording of respiratory, electrodermal, and cardiovascular activity.. Additional recording components such as movement sensors may be used in addition to, but not replace, the required minimum components [13]Verified ASTM E2439 — Standard Guide for Instrumentation, Sensors and Operating Software Used in PDD Examinations
Confirms ASTM standards covering minimum requirements for polygraph instrumentation including simultaneous recording of respiratory, electrodermal, and cardiovascular activity.. If any required sensor is inoperative or malfunctioning, the instrument should not be used for examination purposes.

For more on proper examiner documentation procedures, including the test data sheet requirements, consult our dedicated guide.

Sensor Components Explained

Pneumograph Tubes: Rubber tubes placed around the chest (thoracic) and abdomen measuring respiratory activity — breathing rate, depth, amplitude, and pattern changes. Two channels are required.

Blood Pressure Cuff: A cardio cuff placed on the upper arm recording cardiovascular activity — relative blood pressure changes, pulse rate, and pulse amplitude. Uses a sphygmomanometer gauge. One channel is required.

EDA Sensors: Finger plates or adhesive electrodes measuring electrodermal activity (skin conductance or resistance). Research consistently identifies the electrodermal channel as one of the most diagnostically powerful components in polygraph testing [4]Verified Appendix F: Computerized Scoring of Polygraph Data — National Academies
Confirms CPS was developed by Scientific Assessment Technologies based on Kircher and Raskin research at the University of Utah, and PolyScore was developed at JHU-APL.. One to two channels are required.

Activity Sensors: Motion sensors placed on the seat, under arms, or under feet detecting body movements and physical countermeasure attempts during the examination. One to two channels are required.

Data Acquisition System (DAS): The computer interface that converts analog sensor signals to digital data for display, recording, and analysis via proprietary software. This is the core unit of any computerised polygraph.

Plethysmograph (PPG): An optional finger or earlobe sensor measuring blood volume changes and pulse amplitude. Records vasomotor constriction patterns as an additional physiological channel.

Thumb Cuff: An alternative to the standard arm blood pressure cuff, attached to the thumb when the standard cardio cuff cannot be applied to the arm.

Learn more about how these components work together during a test in our guide on diagnostic impressions in polygraph reports.

Lafayette: LXSoftware and LXEdge

Lafayette's software ecosystem spans two platforms. LXSoftware is the established Windows-based platform compatible with the LX4000, LX5000, LX6, LX7, and Paragon series. It features the Respiration Line Excursion (RLE) tool, ESS-M Interpreter, audio/video synchronisation, report generation, and Mac support via Parallels.

LXEdge is the next-generation platform designed for improved examination efficiency and cross-system compatibility, supporting both the Lafayette LX6/LX7 and Limestone Paragon series [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility.. Supported scoring algorithms include OSS-3, ESS-M, and PolyScore. Examiners can learn more about scoring methodologies in our 7-position scale scoring guide.

Stoelting: CPSpro Fusion

CPSpro Fusion is Stoelting's comprehensive software platform featuring a dynamic question editor, advanced chart recorder, multimedia stimulus support, customisable templates, and secure archiving. The platform imports data from Axciton, Lafayette, and Limestone systems via pREFORMAT.

The integrated CPS scoring algorithm is based on research conducted at the University of Utah psychology laboratory by John Kircher and David Raskin [4]Verified Appendix F: Computerized Scoring of Polygraph Data — National Academies
Confirms CPS was developed by Scientific Assessment Technologies based on Kircher and Raskin research at the University of Utah, and PolyScore was developed at JHU-APL.. CPS was developed by Scientific Assessment Technologies and uses standard multivariate linear discriminant function analysis to calculate an estimate of the probability of truthfulness or deception [4]Verified Appendix F: Computerized Scoring of Polygraph Data — National Academies
Confirms CPS was developed by Scientific Assessment Technologies based on Kircher and Raskin research at the University of Utah, and PolyScore was developed at JHU-APL.. Kircher and Raskin introduced the first computer-assisted polygraph system in 1986, used by the U.S. Secret Service, and the first fully automated system (CPS) in 1991 [5]Verified Your Lying Eyes — University of Utah
Confirms Kircher and Raskin introduced the first computer-assisted polygraph system in 1986 (used by U.S. Secret Service) and the first fully automated CPS in 1991.. CPSpro Fusion also supports the PolyScore algorithm.

Axciton: Suite and STAR Algorithm

Axciton's proprietary platform features an embedded operating system and the STAR (Statistical Test Analysis Report) algorithm — unique to Axciton hardware. The WhiteStar system provides additional automated analysis. Data is exportable in pREFORMAT for cross-platform use in CPSpro Fusion or other scoring systems.

The platform is focused on countermeasure detection and single-issue diagnostic testing, making it a preferred choice for government and counterintelligence applications.

Limestone: Polygraph Pro Suite

Polygraph Pro Suite is a feature-rich platform with an online medical dictionary, automatic EDA modes (GSR/GSC switching), ReportBuilder+ for efficient report generation, text-to-speech question delivery, and an integrated ESS-M scoring interpreter [12]Verified Polygraph Pro Suite Software — Limestone Technologies
Confirms Polygraph Pro Suite software features, ChartSync utility, and Limestone as a subsidiary of Lafayette.. The software also supports OSS-3. Following the 2022 acquisition, the platform is also compatible with Lafayette's LXEdge [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility..

PolyScore Algorithm

PolyScore was developed by the Johns Hopkins University Applied Physics Laboratory (JHU-APL) based on criminal case data provided by the Department of Defense Polygraph Institute [15]Verified The Polygraph and Lie Detection — National Research Council
Confirms PolyScore was developed at JHU-APL, used with Axciton and Lafayette instruments, and details PolyScore Version 5.1 development data.. The algorithm was created by Dr. Dale E. Olsen and John C. Harris at JHU-APL [16]Verified Computerized Polygraph Scoring System — Journal of Forensic Sciences
Confirms PolyScore was developed by Olsen, Harris, Capps, and Ansley at Johns Hopkins APL, published in Journal of Forensic Sciences 1997.. The PolyScore patent was assigned to Johns Hopkins University in 1993 [17]Verified US Patent 5327899A — Polygraph Automated Scoring Systems
Confirms the PolyScore patent was assigned to Johns Hopkins University in 1993, with inventors Harris and Olsen.. The algorithm inputs digitised polygraph signals and outputs a probability of deception based on either a logistic regression or a neural network model [15]Verified The Polygraph and Lie Detection — National Research Council
Confirms PolyScore was developed at JHU-APL, used with Axciton and Lafayette instruments, and details PolyScore Version 5.1 development data.. PolyScore is currently used with both Axciton and Lafayette polygraph instruments [15]Verified The Polygraph and Lie Detection — National Research Council
Confirms PolyScore was developed at JHU-APL, used with Axciton and Lafayette instruments, and details PolyScore Version 5.1 development data..

PolyScore Version 5.1 analysed data from 1,411 real-life criminal cases using Zone Comparison Test and Modified General Question Test data [15]Verified The Polygraph and Lie Detection — National Research Council
Confirms PolyScore was developed at JHU-APL, used with Axciton and Lafayette instruments, and details PolyScore Version 5.1 development data.. The algorithm is in use in more than 40 US states and in countries worldwide [16]Verified Computerized Polygraph Scoring System — Journal of Forensic Sciences
Confirms PolyScore was developed by Olsen, Harris, Capps, and Ansley at Johns Hopkins APL, published in Journal of Forensic Sciences 1997..

OSS-3 Algorithm

The Objective Scoring System version 3 (OSS-3) was published in 2008 by Raymond Nelson, Donald J. Krapohl, and Mark Handler [18]Verified Brute-Force Comparison: A Monte Carlo Study of OSS-3 and Human Polygraph Scorers
Confirms OSS-3 was published in 2008 by Nelson, Krapohl, and Handler as a free and open-source algorithm.. The OSS-3 is described as a free and open-source algorithm, offered openly to the polygraph community, with none of the authors holding any financial interest in it [19]Verified OSS-3 Disclaimer — Polygraph Journal
Confirms OSS-3 was developed as an open-source project with no financial interest by the authors, offered openly to the polygraph community.. The algorithm was developed to provide an objective and scientifically defensible method for analysing polygraph data [19]Verified OSS-3 Disclaimer — Polygraph Journal
Confirms OSS-3 was developed as an open-source project with no financial interest by the authors, offered openly to the polygraph community..

OSS-3 demonstrated balanced sensitivity and specificity and provided significant improvements over previous scoring methods [18]Verified Brute-Force Comparison: A Monte Carlo Study of OSS-3 and Human Polygraph Scorers
Confirms OSS-3 was published in 2008 by Nelson, Krapohl, and Handler as a free and open-source algorithm.. It is now integrated across Lafayette and Limestone platforms, and its evidence-based approach has helped transform polygraph data analysis across the profession [20]Verified Monte Carlo Study of DLST — APA
Confirms OSS-3 as a free and open-source cross-platform algorithm available to all PDD manufacturers, field examiners and researchers.. For a comprehensive understanding of scoring and data analysis techniques, explore our Directed Lie Screening Test guide.

A Timeline of Technology Milestones

1921 — John A. Larson at UC Berkeley constructed the first instrument to continuously record multiple physiological channels simultaneously — respiratory and cardiovascular data — during police questioning.

1930s — Leonarde Keeler added the galvanic skin response (EDA) channel to the existing cardiovascular and respiratory components, creating the multi-channel instrument recognisable as the modern polygraph. The Keeler Polygraph became the industry standard.

1935 — Stoelting created their first cardio-pneumo polygraph, initiating its psychophysiology division [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978..

1947 — Max Wastl established Lafayette Instrument Company in Indiana with a single employee and a small shed [1]Verified Our Story — Lafayette Instrument Company
Confirms Max Wastl founded Lafayette Instrument Company in 1947, the 2016 founding of PEAK, and the 2022 acquisition of Limestone Technologies.. That same year, John E. Reid developed the Control Question Technique (CQT).

1951 — The Reid Polygraph was introduced by Stoelting [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978..

1958 — The Stoelting Deceptograph was standardised by the US military [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978..

1974 — Stoelting released the Polyscribe — the world's first all-electronic polygraph instrument — replacing purely mechanical pen-and-paper recording [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978.. The Ultrascribe followed in 1978 [9]Verified Stoelting — Wikipedia
Confirms Stoelting's 1886 founding, first cardio-pneumo polygraph in 1935, Polyscribe in 1974, and Ultrascribe in 1978..

1986 — David Raskin and John Kircher at the University of Utah introduced the first computer-assisted polygraph system (CAPS), which was used by the U.S. Secret Service [5]Verified Your Lying Eyes — University of Utah
Confirms Kircher and Raskin introduced the first computer-assisted polygraph system in 1986 (used by U.S. Secret Service) and the first fully automated CPS in 1991..

1990 — The first commercially viable computerised polygraph system came from the Axciton Corporation in Houston, Texas, incorporating both software and hardware [10]Verified Polygraph Test — ScienceDirect Topics
Confirms in 1990 the first commercially viable computerised polygraph came from Axciton Corporation in Houston; Raskin and Kircher developed a system about 2 years earlier..

1991 — Kircher and Raskin introduced the first fully automated Computerised Polygraph System (CPS), which is still used worldwide today [5]Verified Your Lying Eyes — University of Utah
Confirms Kircher and Raskin introduced the first computer-assisted polygraph system in 1986 (used by U.S. Secret Service) and the first fully automated CPS in 1991..

1993 — Dr. Dale E. Olsen and John C. Harris at Johns Hopkins University Applied Physics Laboratory completed the PolyScore algorithm [16]Verified Computerized Polygraph Scoring System — Journal of Forensic Sciences
Confirms PolyScore was developed by Olsen, Harris, Capps, and Ansley at Johns Hopkins APL, published in Journal of Forensic Sciences 1997., with the patent assigned to Johns Hopkins University [17]Verified US Patent 5327899A — Polygraph Automated Scoring Systems
Confirms the PolyScore patent was assigned to Johns Hopkins University in 1993, with inventors Harris and Olsen..

2008 — Nelson, Krapohl, and Handler published the OSS-3 scoring algorithm as a free, open-source project [18]Verified Brute-Force Comparison: A Monte Carlo Study of OSS-3 and Human Polygraph Scorers
Confirms OSS-3 was published in 2008 by Nelson, Krapohl, and Handler as a free and open-source algorithm. [19]Verified OSS-3 Disclaimer — Polygraph Journal
Confirms OSS-3 was developed as an open-source project with no financial interest by the authors, offered openly to the polygraph community.. The algorithm demonstrated balanced accuracy and contributed to a more objective approach to polygraph data analysis across all platforms.

2016 — Lafayette founded the PEAK Credibility Assessment Training Center, offering APA-accredited examiner training [6]Verified About PEAK — PEAK Credibility Assessment Training Center
Confirms PEAK was founded in 2016 by Ben Blalock with Lafayette Instrument, is APA-accredited and AAPP-recognised, now located in Lakeland, FL..

2022 — Lafayette Instrument Company acquired Limestone Technologies in August 2022 [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility., uniting the LX6 and ParagonX product lines. LXEdge software platform was designed for cross-system compatibility.

Today — Modern polygraph systems achieve 625 samples/sec/channel [3]Verified ParagonX Polygraph System — Lafayette Instrument
Confirms ParagonX native 625 samples/sec/channel, Lemo connectors, dual-channel 32-bit acquisition, and LXEdge compatibility., integrate validated algorithms (OSS-3, PolyScore, ESS-M, CPS, STAR), and support AI-enhanced statistical pre-screening alongside examiner-led scoring. All major manufacturers now produce exclusively digital instruments.

Key Factors for Your Decision

Selecting the right polygraph instrument requires careful consideration of several factors. Before purchasing, consult with experienced users, attend manufacturer demonstrations where possible, and ensure compatibility with the validated testing formats you use most frequently.

Testing Context: Match the system to your primary testing environment. Federal and counterintelligence work may favour Axciton's countermeasure-focused design. PCSOT and clinical programmes may benefit from the ParagonX's high-resolution waveforms. General private practice is well-served by Lafayette's broad ecosystem and support infrastructure.

Scoring Compatibility: Ensure the system supports the validated scoring algorithms you plan to use. OSS-3 and ESS-M are available on Lafayette and Limestone platforms. PolyScore runs on Lafayette and Stoelting. Axciton's STAR is proprietary. Cross-platform data export via pREFORMAT enables second-opinion scoring.

Agency Compliance: Federal agencies may specify approved manufacturers or software platforms. Verify that your chosen system meets the requirements of your agency, state licensing board, and APA/ASTM standards before committing. ASTM Committee E52 standards are now widely cited by polygraph organisations and recognised in courts [21]Verified Would I Lie To You? — ASTM Standardization News
Confirms ASTM Committee E52 on Forensic Psychophysiology was officially recognised in 1998 and that ASTM standards are widely cited by polygraph organisations and courts..

Software Ecosystem: Evaluate the complete software package — not just chart recording, but question templates, report generation, audio/video sync, quality control tools, and scoring integration. Modern platforms like LXEdge and CPSpro Fusion offer comprehensive examination management.

Training and Support: Consider the manufacturer's training offerings, technical support, software updates, and user community. Lafayette's PEAK Training Center and Stoelting's training partnerships offer hands-on instruction. For examiners starting their careers, our become a polygraph examiner hub has comprehensive career guidance, and those interested in Africa can explore accredited polygraph training schools on the continent.

Upgrade and Trade-In: All major manufacturers offer trade-in or upgrade programmes for existing systems. The ParagonX upgrade programme offers trade credit for older models or competitor systems. Lafayette's LX6 upgrade path preserves existing accessories and sensor investments. See our polygraph test pricing for information on our all-inclusive examination fees.