Polygraph Instrument Comparison Chart 2026: Buyer’s Guide

A Market Shaped by Digital Transformation and Consolidation

The polygraph instrument market in 2025 reflects both decades of digital transformation and significant corporate consolidation. The complete transition from analog to digital systems is long finished, and the competitive landscape has consolidated around three primary independent manufacturers and one subsidiary: Lafayette Instrument Company, Stoelting Company, Axciton Systems, and Limestone Technologies (now a subsidiary of Lafayette) [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022.

The most significant recent development in the equipment market was Lafayette Instrument Company's acquisition of Limestone Technologies in August 2022 [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. This acquisition expanded Lafayette's product line, staff, and international market reach, and means that two of the four major polygraph brands — Lafayette and Limestone — are now under common ownership [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022. Despite this consolidation, Limestone continues to operate its ParagonX product line and Polygraph Professional Suite software as distinct offerings.

A modern polygraph system is not simply a piece of hardware — it is an integrated platform consisting of physiological sensors, a data acquisition unit, proprietary software for recording and scoring, and an ongoing service relationship with the manufacturer. When you purchase a polygraph instrument, you are buying into an ecosystem, and switching costs can be significant. Understanding how the market has evolved is essential for making a smart purchasing decision. For a deeper understanding of the instruments themselves, explore our complete technical guide to polygraph instruments.

Why This Comparison Matters

Unlike consumer electronics, there are no independent review sites for polygraph equipment. Most examiners rely on word-of-mouth, training school recommendations, or manufacturer marketing materials. A polygraph instrument represents one of the largest capital investments an examiner will make, with downstream consequences for workflow efficiency, exam quality, and professional credibility.

This guide organizes specifications from manufacturer documentation and industry publications to enable genuine apples-to-apples comparison across the key dimensions that matter for professional use: channel count, sensor technology, software capabilities, scoring algorithms, portability, and pricing. For those considering career paths that require equipment proficiency, our guide on how to become a certified PCSOT examiner covers what employers expect.

Lafayette Instrument Company

Founded in 1947 by Max Wastl, a German immigrant who studied Electrical Engineering at Purdue University, Lafayette Instrument Company began as a one-man operation in an 8 x 10 foot shed in Lafayette, Indiana [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022. Today, it is widely regarded as the dominant force in the polygraph equipment market and the global leader in polygraph instruments, distributing credibility assessment solutions to most federal law enforcement and government security agencies [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022.

Lafayette's current flagship products include the LX6 — a 10-channel polygraph system — and the next-generation LX7, which introduces advanced features such as Pulse Arrival Time (PAT) measurement via improved PPG sensors [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. The company's LXSoftware platform is bundled with the Objective Scoring System (OSS-3) scoring algorithm, one of the most extensively validated computer scoring algorithms in polygraph research [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity. Lafayette also offers LXEdge, their next-generation software platform that is compatible with the LX6, LX7, and Limestone Paragon series [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement.

In 2016, Lafayette founded the PEAK Credibility Assessment Training Center to teach scientifically validated credibility assessment techniques [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022. In 2022, the company acquired Limestone Technologies, further reinforcing its commitment to the polygraph market [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. For examiners who work in federal contracting, law enforcement, or PCSOT testing, Lafayette instruments are often the expected or required standard. Learn more about the Lafayette OSS-3 algorithm in our dedicated technical guide.

Stoelting Company

The Stoelting Company brings the deepest historical pedigree to the polygraph market. Founded in 1886 as the Chicago Laboratory Supply and Scale Company by Christian Hans Stoelting, the firm has been manufacturing scientific instruments for over 135 years [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Stoelting created their first Cardio-Pneumo Polygraph in 1935 and has been a pioneer in the field ever since [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Their Deceptograph model became a foundational instrument, with the model 22500 standardized by the US military in 1958 [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system.

Today, Stoelting's current flagship is the CPS Elite, which has replaced the older CPS Pro line [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. The CPS Elite is notable for being the only polygraph unit with a built-in full-color LCD touchscreen display, providing active feedback and allowing examiners to verify sensor function without leaving the examinee [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Stoelting's CPS Fusion software powers the Elite and offers an intuitive interface with comprehensive charting, scoring, and reporting capabilities. The software can also import data from Axciton, Lafayette, or Limestone systems exported in pREFORMAT [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. For a detailed look at Stoelting's software, see our CPS Pro Software feature guide and CPS Elite system review.

Stoelting is headquartered in Wood Dale, Illinois, and offers both mechanical and Piezo electronic respiration sensors — making it the only manufacturer to offer Piezo sensors for recording respiration, a technology preferred in laboratory settings [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. The company also offers polygraph training including a Basic Examiner's Course and a PCSOT training course.

Axciton Systems

Axciton Systems, based in Houston, Texas, occupies a distinctive and historically significant position in the polygraph equipment market [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. Bruce White of Axciton Systems began researching the production and transfer from analog to digital polygraph in 1988, and in 1990, Axciton produced what is widely recognized as the first commercially viable computerized polygraph system [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. The software and devices were developed in conjunction with the work of David Raskin and John Kircher at the University of Utah [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago.

Axciton's current Professional Series features the proprietary STAR (Statistical Typing Algorithm for Reliability) scoring algorithm, which uses convolutional deconstruction of polygraph channels and has demonstrated 93% NDI accuracy with confirmed results [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. The system also includes the patented Motion Sensor Pad, which uses piezoelectric technology to detect foot and gluteal countermeasures without requiring separate connections [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. For a head-to-head analysis, see our Axciton vs. Stoelting comparison guide.

Axciton has maintained a particularly strong following among private practice examiners and government agencies who appreciate the responsive customer service and competitive pricing. The company has been exclusively focused on computerized polygraph systems for over 25 years [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago.

Limestone Technologies (Lafayette Subsidiary)

Limestone Technologies, originally headquartered in Kingston, Ontario, Canada, was acquired by Lafayette Instrument Company on August 12, 2022 and now operates as a Lafayette subsidiary [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. Despite the acquisition, Limestone maintains its distinct product line and brand identity, continuing to serve examiners worldwide with its ParagonX system and Polygraph Professional Suite software.

The ParagonX system features dual-channel 32-bit data acquisition with optical isolation greater than 5000mV, and boasts the highest native sampling rate of any polygraph instrument at 625 samples per second per channel [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. The system uses flush-mounted nickel-plated brass Lemo precision connectors for all nine inputs, providing medical-grade connection quality [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. Limestone's Polygraph Professional Suite was first introduced in 2003 and has been internationally recognized in the credibility assessment field [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. The software also integrates OSS-1, OSS-2, and OSS-3 scoring algorithms [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel.

A key advantage of the Limestone-Lafayette relationship is cross-platform compatibility — Lafayette's LXEdge software is compatible with the ParagonX system, giving examiners flexibility in their software choice [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Limestone continues to offer competitive pricing and strong international presence, particularly in Canadian and Commonwealth markets.

Complete Feature Comparison

The following comparison represents specifications gathered from manufacturer documentation. Note that Limestone Technologies is now a subsidiary of Lafayette Instrument Company, though both product lines continue to be sold and supported independently.

Lafayette LX6: 10 data channels [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement, 32-bit A/D resolution, USB connectivity, LXSoftware with OSS-3 scoring, Fischer quick-release connectors, compatible with Windows operating systems. Also compatible with LXEdge next-generation software. 10-channel configuration includes dual pneumograph (thoracic and abdominal), EDA/GSR, cardiovascular cuff, PPG/plethysmograph, and activity sensors [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement.

Lafayette LX7: Next-generation system with 32-bit data resolution at 180 samples per second across all channels, 5000Vrms isolation on all channels, ABS/Polycarbonate enclosure, USB powered [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Features improved PPG sensor for Pulse Arrival Time (PAT) measurement, compatible with LXSoftware and LXEdge. Supports LX6 accessories. Dimensions: 8.66" x 3.61" x 1.21" [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement.

Stoelting CPS Elite: Features built-in LCD touchscreen display, sampling at 360 samples per second, USB powered, CPS Fusion software [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Offers both mechanical and Piezo electronic respiration sensors. Configurable up to 8+ channels including expansion movement sensors for arms, feet, and masseter headset [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Fourth-generation Computerized Polygraph System [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system.

Axciton Professional Series: 5-channel USB sensor box packages available, STAR proprietary scoring algorithm with 93% NDI accuracy, patented Motion Sensor Pad with piezoelectric technology [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. Whitestar algorithm and Devagus-Despike adaptive filters for artifact suppression [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago.

Limestone ParagonX: 9-channel system with dual-channel 32-bit acquisition, 625 samples per second per channel (highest in industry), Lemo precision connectors, CE certified [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. Polygraph Professional Suite software with OSS-1/2/3 integration, ChartSync multimedia synchronization [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. Compatible with Lafayette LXEdge software.

All systems feature USB connectivity, computerized scoring capabilities, Windows compatibility, and meet APA instrumentation requirements. Specifications may vary by specific model configuration — contact manufacturers directly for current quotes and detailed specifications.

APA Instrumentation Requirements

The American Polygraph Association's Standards of Practice (most recently amended August 23, 2024) establish instrumentation requirements for polygraph examination [6]Verified APA Standards of Practice Document
Confirms instrumentation requirements including dual pneumograph, EDA, cardiovascular, and activity sensor channels. At minimum, examinations require recording of respiration patterns via pneumograph components, with thoracic and abdominal patterns recorded separately using two channels, along with electrodermal activity (EDA), cardiovascular activity, and a seat activity sensor [6]Verified APA Standards of Practice Document
Confirms instrumentation requirements including dual pneumograph, EDA, cardiovascular, and activity sensor channels.

Modern best practices strongly encourage additional channels beyond this minimum. Activity sensors for movement detection, photoplethysmograph (PPG) sensors for peripheral vasomotor activity, and countermeasure detection sensors have become essential components of comprehensive examinations, particularly in high-stakes testing environments. Research has consistently demonstrated that additional data channels improve diagnostic accuracy — as confirmed in studies examining the impact of channel counts on scoring outcomes [9]Verified Comparison of Utah and DoDPI Scoring Accuracy
Foundational research demonstrating that scoring accuracy depends on decision rules, chart rules, and data channels used rather than scorer identity. For a thorough understanding of how polygraph questions are reviewed before testing, visit our dedicated guide.

Why More Channels Matter

Additional channels provide more data points for analysis, translating to greater diagnostic accuracy and stronger defensibility of results. Activity sensors — typically seat cushion sensors and sometimes arm rest or foot sensors — help identify deliberate countermeasure attempts by detecting physical movements that might otherwise be invisible to the examiner. Our guide on breath hold countermeasure detection explains how modern sensors identify these attempts.

The PPG channel provides an independent measure of cardiovascular activity that can corroborate or complement the traditional blood pressure cuff data. Lafayette's LX7 takes this further with its PAT (Pulse Arrival Time) measurement, which calculates the time between the ECG pulse and PPG waveform — a measurement directly correlated to blood pressure [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Research has found that PAT is as effective as the cardiograph for discriminating between truthful and deceptive people in a polygraph test [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Historical research on cardiovascular measurement, including the foundational comparison of arm-cuff and wrist-cuff blood pressure patterns by Norman Ansley (1959), has helped standardize the instrumentation methods used across all modern systems [10]Verified A Comparison of Arm-Cuff and Wrist-Cuff Blood Pressure Patterns in Polygraph Charts
Foundational research on blood pressure monitoring methods that contributed to standardization of polygraph instrumentation.

Sensor Technology Differences Between Manufacturers

While all manufacturers offer the same basic sensor types, important differences exist in how they record physiological data. One crucial difference lies in the electrodermal channel: Stoelting records skin conductance, Lafayette records skin resistance (requiring additional filtering to stabilize the baseline), and Axciton uses a hybrid of skin resistance and skin conductance [11]Verified Appendix F: Computerized Scoring of Polygraph Data — The Polygraph and Lie Detection
Documents differences in how Lafayette, Stoelting, and Axciton record electrodermal signals, and describes CPS and PolyScore algorithm architectures. These differences, documented by the National Research Council in their landmark 2003 report, affect signal processing and can influence how algorithms interpret the data.

Stoelting uniquely offers Piezo electronic sensors for recording respiration as an alternative to traditional mechanical pneumographs [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Piezo sensors are preferred in laboratory settings for their precision. Lafayette's sensors feature Fischer quick-release connectors rated for twice the mating cycles of connectors used by other manufacturers [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Limestone's ParagonX uses medical-grade Lemo precision connectors [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel.

Regardless of manufacturer, all sensors are consumable items that require periodic replacement. Pneumograph tubes lose elasticity over time, EDA plates develop surface corrosion, and blood pressure bladders eventually fail. When calculating total cost of ownership, factor in sensor replacement costs as a recurring expense. For a complete overview of accessories, see our polygraph accessories buyer's guide.

The Software Is the Instrument

In modern polygraph practice, the software platform is arguably more important than the hardware itself. The data acquisition unit captures physiological signals, but the software is where examiners spend their working lives — recording charts, adjusting sensitivity settings, marking questions, reviewing tracings, running scoring algorithms, generating reports, and managing case files. Software usability, feature depth, and reliability directly impact an examiner's productivity and quality of work.

Lafayette LXSoftware and LXEdge

LXSoftware is the most widely adopted polygraph software platform on the market. It is bundled with the Objective Scoring System (OSS-3) scoring algorithm [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity and includes comprehensive chart markup tools, RLE (Ratio of Line Excursion) measurement tools for pneumograph scoring, side-by-side chart comparison, detailed numerical scoring outputs, and robust case management [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. The software is compatible with Lafayette LX4000, LX5000, LX6, and LX7 systems [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement and supports Mac use via Parallels or other virtualization software.

Lafayette's newest software platform, LXEdge, is designed for the future and is compatible with the LX6, LX7, and Limestone Paragon series [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. This cross-platform compatibility represents a significant advantage for examiners who may need to work across different hardware platforms within the Lafayette/Limestone ecosystem.

The OSS-3 algorithm was developed by Raymond Nelson, Donald Krapohl, and Mark Handler and validated using brute-force statistical methods against both previously described scoring algorithms and human examiners [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity. Published in the journal Polygraph in 2008, the validation study used confirmed single-issue field investigation polygraphs (N=292 development sample, N=100 validation sample) and demonstrated balanced sensitivity and specificity [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity. The algorithm provides an open-source, objective, and scientifically defensible method for analyzing polygraph data [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity. For complete details, see our OSS-3 algorithm technical guide.

Stoelting CPS Fusion Software

CPS Fusion is Stoelting's current-generation software, powering the CPS Elite system and also available for older CPS Pro hardware [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Designed from the ground up, CPS Fusion features an intuitive interface where virtually all functions can be accomplished with a single click [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. The software includes advanced charting, scoring, and report generation capabilities with numerical scores and subtotals for each relevant question, each chart, and each physiological component [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system.

A notable feature of CPS Fusion is its interoperability — users can import data from Axciton, Lafayette, or Limestone systems as long as it was exported in pREFORMAT [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. The CPS scoring algorithm is based on standard multivariate linear discriminant function analysis developed at the University of Utah, producing an estimate of the probability of truthfulness or deception [11]Verified Appendix F: Computerized Scoring of Polygraph Data — The Polygraph and Lie Detection
Documents differences in how Lafayette, Stoelting, and Axciton record electrodermal signals, and describes CPS and PolyScore algorithm architectures.

Axciton Computerized Polygraph Software

Axciton's proprietary software platform supports the entire examination workflow from pre-test setup through chart review and reporting [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. Key differentiators include the STAR algorithm for automated scoring, the Whitestar algorithm, and Devagus-Despike adaptive filters for artifact suppression and movement noise control [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. The software offers dual-mode (3/7-point) hand scoring with expandable scoring tables and visually resizable windows [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. Axciton has historically also utilized PolyScore algorithms developed at the Johns Hopkins University Applied Physics Laboratory, along with their proprietary Chart Analysis and AXCON algorithms [11]Verified Appendix F: Computerized Scoring of Polygraph Data — The Polygraph and Lie Detection
Documents differences in how Lafayette, Stoelting, and Axciton record electrodermal signals, and describes CPS and PolyScore algorithm architectures.

Limestone Polygraph Professional Suite

Limestone's Polygraph Professional Suite was first introduced in 2003 and features a user-friendly design with time-saving features packaged into an easy-to-navigate front-end management system [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. The software integrates OSS-1, OSS-2, and OSS-3 scoring algorithms [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel and includes the ChartSync utility, which synchronizes video, audio, and chart data for comprehensive chart review [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. The software also supports audio and visual stimulus integration for testing, multi-language capability (including French), and an open data format — making Limestone the first polygraph vendor to offer unrestricted access to raw examination data [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel.

The Role of Computerized Scoring in Modern Practice

Peer-reviewed research has demonstrated that computerized scoring algorithms can meet or exceed human experts in polygraph decision-making [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity. The OSS-3 algorithm provides perfect reliability — identical results every time the same data is analyzed — which is a critical advantage for quality assurance [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity. The Empirical Scoring System (ESS) has achieved bootstrap mean accuracy rates of 87.9% in validation studies, with inexperienced examiners demonstrating decision accuracy comparable to experienced scorers when using ESS [8]Verified Brute-Force Comparison: A Monte Carlo Study of the OSS-3 and Human Polygraph Scorers
Confirms Nelson, Krapohl & Handler (2008) developed OSS-3, validated with N=292 and N=100 confirmed field cases, demonstrating balanced sensitivity and specificity.

The largest meta-analysis ever conducted on comparison question polygraph testing, analyzing 138 datasets, found a meta-analytic effect size of 0.69 including inconclusives, with motivation level showing a positive linear relationship with accuracy [12]Verified A Comprehensive Meta-Analysis of the Comparison Question Polygraph Test
Largest meta-analysis ever conducted on CQT, analyzing 138 datasets, found meta-analytic effect size of 0.69 including inconclusives. Earlier meta-analytic research found overall accuracy estimates above 85% across studies when examining moderator variables including examiner training, question format, and testing protocols [13]Verified A Meta-Analysis of the Comparison Question Polygraph Test: Moderator Effects
Found overall accuracy estimates above 85% across studies with important moderator variables including examiner training and testing protocols. These findings underscore that computerized scoring supplements — but does not replace — examiner judgment. The research literature supports computerized scoring as a valuable tool that improves consistency and reduces subjectivity, while final diagnostic opinions still require trained human analysis. For more on accuracy research, see the foundational comparison of scoring accuracy by Senter (2000) [9]Verified Comparison of Utah and DoDPI Scoring Accuracy
Foundational research demonstrating that scoring accuracy depends on decision rules, chart rules, and data channels used rather than scorer identity.

Why Portability Matters

Many polygraph examiners spend a significant portion of their working lives traveling to examination sites. Private practice examiners travel to attorneys' offices, corporate facilities, and client locations. Law enforcement examiners may need to conduct tests at substations or satellite offices. PCSOT examiners frequently rotate between probation offices, treatment facilities, and their own offices. Understanding the ideal conditions for a lie detector test helps examiners select equipment that performs well in diverse environments.

All four manufacturers have designed their current instruments with portability in mind. Modern data acquisition units are compact, lightweight, and USB-powered, eliminating the need for separate power supplies. The LX7 measures just 8.66" x 3.61" x 1.21" and draws all power through USB [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. The ParagonX features a compact design with a Pelican instrument case [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. Stoelting's CPS Elite is similarly portable with USB power delivery [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system.

Hardware Build Quality Comparison

Lafayette's LX6 and LX7 hardware feature rugged molded and textured enclosures designed for added stability, with the LX7 built from polycarbonate blend for superior toughness, durability, impact resistance, and heat resistance [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Fischer connectors on Lafayette systems feature a quick-release mechanism and are rated for twice the mating cycles of connectors used by other manufacturers, ensuring long-term reliability through repeated connection cycles [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement.

Stoelting's CPS Elite reflects over 135 years of manufacturing heritage with its built-in touchscreen display providing a distinctive advantage for field examiners — sensor status can be verified without returning to the computer [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. The Elite is the only polygraph with this built-in display capability [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system.

Limestone's ParagonX uses medical-grade Lemo connectors with a patented push-pull latching system for secure, ruggedized connections [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. The system is CE certified, meeting European safety and electromagnetic compatibility standards [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel.

Axciton hardware is functional and reliable, built for the demands of daily professional use with durable sensor box packages [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. For guidance on transporting equipment, see our polygraph equipment financing guide.

Understanding Pricing Structures

Polygraph system pricing varies significantly based on configuration, included accessories, and software licensing. Lafayette offers a lease-to-own program where monthly payments can be covered after a few exams, with full ownership after 36 months and full DAS warranty for the life of the lease [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Trade-in programs are available from multiple manufacturers — Lafayette offers trade-in discounts on new LX6 and LX7 systems for current polygraph owners, and Limestone's ParagonX offers up to $2,700 in trade credit for older models or competitor systems [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago.

Total cost of ownership extends beyond the initial purchase price. Factor in recurring costs including sensor replacement (pneumograph tubes, EDA electrodes, blood pressure bladder assemblies), software updates, continuing education requirements, and laptop/computer upgrades. The APA requires practicing examiners to complete a minimum of 30 continuing education hours every two years [6]Verified APA Standards of Practice Document
Confirms instrumentation requirements including dual pneumograph, EDA, cardiovascular, and activity sensor channels, and equipment proficiency training is an important component of that requirement.

For detailed financing options, explore our polygraph equipment financing guide. For broader guidance on system selection, see our buyer's guide for choosing the right polygraph system.

Warranty Coverage

Lafayette offers a full DAS warranty for the life of the lease and one year warranty on system accessories for leased systems [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. For purchased systems, standard warranty terms apply. Stoelting, Axciton, and Limestone offer standard warranty coverage — typically 1-2 years depending on the component and purchase terms. Limestone notably offers lifetime technical support and replacement coverage for the ParagonX instrument [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel.

Beyond warranty, the manufacturer service relationship matters. Lafayette and Limestone (as subsidiaries under common ownership) share support infrastructure from their Lafayette, Indiana headquarters [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022. Stoelting provides support from Wood Dale, Illinois [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system. Axciton offers direct customer service from Houston, Texas, emphasizing personal attention and quick-turnaround software updates [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago.

Key Decision Factors

Selecting a polygraph instrument requires evaluating several interrelated factors. Training program compatibility is paramount — many APA-accredited polygraph training schools teach on specific equipment platforms, and starting with the same equipment you trained on eliminates a learning curve. PEAK Credibility Assessment Training Center, which is owned by Lafayette Instrument Company, naturally teaches on Lafayette and Limestone equipment [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022.

Your primary examination type also matters. Federal agency and law enforcement examiners will find Lafayette's LX6 and LX7 to be the expected standard, with the strongest adoption among government organizations [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022. PCSOT examiners benefit from robust countermeasure detection capability — Axciton's Motion Sensor Pad and Stoelting's expansion movement sensors both provide multi-point countermeasure monitoring [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system[3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. Private practice examiners may prioritize portability and value, where all manufacturers offer competitive solutions.

Recommendations by Examiner Type

For federal and law enforcement examiners: The Lafayette LX6 or LX7 is the natural choice given dominant adoption among government agencies and the most extensive scoring algorithm validation through the OSS-3 [1]Verified Lafayette Instrument Company - Our Story and Company History
Confirms Lafayette Instrument Company was founded in 1947 by Max Wastl in Lafayette, Indiana, and acquired Limestone Technologies in 2022[7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement.

For PCSOT and sex offender supervision examiners: Any of the four platforms can serve well, but robust countermeasure detection is essential. Axciton's STAR algorithm and Motion Sensor Pad offer strong countermeasure resistance [3]Verified Axciton Systems, Inc. - Official Website and Product Information
Confirms Axciton was the first company to produce a usable computerized polygraph system over 25 years ago. Learn more about PCSOT programs and their equipment requirements.

For private practice examiners: Evaluate total cost of ownership carefully. Axciton and Limestone/ParagonX may offer competitive entry points while still providing professional-grade capability. Consider trade-in programs if upgrading from an older system.

For international examiners: The Limestone ParagonX, with its international heritage and CE certification, has strong presence in Canadian and Commonwealth markets [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel. Lafayette systems also have strong international distribution.

For training schools: Lafayette's extensive product line (LX6, LX7, ParagonX, LXSoftware, LXEdge, Polygraph Professional Suite) provides the most flexibility for teaching across multiple platforms under a single manufacturer relationship.

Emerging Technologies and Trends

Several trends are shaping the next generation of polygraph instruments. Lafayette's LX7 introduces Pulse Arrival Time (PAT) measurement, which calculates the time between the ECG pulse and PPG waveform — a measurement directly correlated to blood pressure [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. This technology supports research into potentially replacing the traditional blood pressure cuff with non-invasive PPG-based cardiovascular measurement, which could significantly improve examinee comfort during lengthy examination sessions.

High-fidelity sampling continues to advance, with the Limestone ParagonX already exceeding 625 Hz per channel [4]Verified Limestone Technologies - Products and Company Information
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022, ParagonX specifications including 625 samples/second/channel and Lafayette's systems moving to higher resolution 32-bit data acquisition [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. Software ecosystems are also evolving — the integration of multimedia stimulus, customizable question templates, and secure chart archiving is now standard across all major systems. Understanding the various polygraph test formats helps examiners appreciate how these technological advances translate to improved examination quality.

Cross-platform data compatibility is another important trend. Stoelting's CPS Fusion can import data from competing platforms [2]Verified Stoelting Company - Our Company History
Confirms Stoelting was founded in 1886, created first polygraph in 1935, and the CPS Elite is the current flagship system, and Lafayette's LXEdge works across multiple hardware systems [7]Verified Lafayette LX6 and LX7 Polygraph System Specifications
Confirms LX6 is a 10-channel system with 32-bit resolution, Fischer connectors, and LXSoftware/LXEdge compatibility; LX7 features PAT measurement. This interoperability benefits the profession by reducing lock-in effects and facilitating quality assurance across agencies using different equipment. The dispelling of common polygraph misconceptions continues to build public confidence in the technology.