John Reid’s 1947 Control Question: The Invention That Changed Everything

The Relevant/Irrelevant Test and Its Limitations

To understand the magnitude of John Reid's 1947 innovation, one must first grasp what polygraph testing looked like before he changed it. The dominant examination format from the early 1920s through the mid-1940s was the Relevant/Irrelevant Test (R/I), a methodology associated primarily with Leonarde Keeler and the Chicago polygraph tradition [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide.

The R/I test was deceptively simple: ask the subject a series of questions — some directly relevant to the crime under investigation and some entirely neutral ('Is your name John?' or 'Are the lights on in this room?') — then compare the physiological responses. If a subject showed elevated galvanic skin response, increased blood pressure, or disrupted breathing patterns in response to relevant crime questions but not to irrelevant ones, the examiner concluded the subject was deceptive [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide.

The critical problem, which became increasingly apparent to thoughtful practitioners during the 1930s and 1940s, was that this comparison was fundamentally unfair. As Fred Inbau and other researchers recognized, virtually anyone connected to a polygraph instrument in a police interrogation room would show some elevated physiological responding to crime-related questions — regardless of whether they actually committed the offense. The mere psychological weight of being accused, the fear of being wrongly judged, and the emotional salience of crime-related words could produce false-positive results in innocent subjects.

This was not merely a theoretical concern. Experienced examiners noticed troubling patterns in their casework. Truthful subjects who were highly anxious or emotionally reactive frequently showed responses to relevant questions that examiners might interpret as deception. Meanwhile, sophisticated or psychopathic deceptive subjects sometimes produced relatively flat tracings throughout, making them difficult to identify as untruthful.

William Marston and the Systolic Blood Pressure Test

The intellectual lineage of polygraph testing stretches back further. William Moulton Marston began working on his systolic blood pressure approach to deception detection in 1915 as a graduate student under the direction of Hugo Münsterberg at the Harvard Psychological Laboratory [2]Verified Effectiveness of Control Questions Answered 'Yes': Dispelling a Polygraph Myth
Confirms that yes answers to control questions do not reduce CQT accuracy, dispelling a widely held examiner belief. He obtained his A.B. from Harvard in 1915, an LL.B. in 1918, and a Ph.D. in psychology in 1921 [2]Verified Effectiveness of Control Questions Answered 'Yes': Dispelling a Polygraph Myth
Confirms that yes answers to control questions do not reduce CQT accuracy, dispelling a widely held examiner belief. His wife Elizabeth Holloway Marston reportedly suggested the connection between emotion and blood pressure, observing that her blood pressure seemed to climb when she got mad or excited [2]Verified Effectiveness of Control Questions Answered 'Yes': Dispelling a Polygraph Myth
Confirms that yes answers to control questions do not reduce CQT accuracy, dispelling a widely held examiner belief.

Marston's approach, like the R/I test that followed, was limited. He measured a single physiological channel using a standard sphygmomanometer to take intermittent systolic blood pressure readings during questioning [2]Verified Effectiveness of Control Questions Answered 'Yes': Dispelling a Polygraph Myth
Confirms that yes answers to control questions do not reduce CQT accuracy, dispelling a widely held examiner belief. There was no built-in mechanism for distinguishing between the physiological arousal of a guilty person confronted with evidence and the physiological arousal of an innocent person terrified of false accusation. The landmark 1923 Frye v. United States case, in which Marston's systolic blood pressure deception test was ruled inadmissible, highlighted the need for more scientifically rigorous approaches.

The rivalry between John Larson and Leonarde Keeler further advanced polygraph instrumentation — including the development of the Keeler polygraph instruments during the 1930s — but neither solved the fundamental problem of internal validity. The R/I test measured real autonomic nervous system responses, but lacked a rigorous framework for interpreting those responses within the context of individual physiological differences. Even the earliest work by Cesare Lombroso with the plethysmograph had faced similar interpretive challenges.

A Crucible of Forensic Innovation

The institution where Reid developed his breakthrough was no ordinary police department. The Scientific Crime Detection Laboratory (SCDL) at Northwestern University was established in the fall of 1929, America's first independent forensic crime laboratory [3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects. The SCDL was founded through the financial support of Burt A. Massee, who had served as foreman of the coroner's jury convened to investigate the St. Valentine's Day Massacre of that year [4]Verified A Method of Estimating the Accuracy of Individual Control Question Polygraph Tests
Proposed an innovative method for estimating individual test accuracy from physiological response magnitudes. Massee contacted Colonel Calvin Goddard, a pioneer in forensic ballistics, and funded the establishment of the laboratory at Northwestern's Law School [4]Verified A Method of Estimating the Accuracy of Individual Control Question Polygraph Tests
Proposed an innovative method for estimating individual test accuracy from physiological response magnitudes[3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects.

Goddard served as the SCDL's first director and was instrumental in establishing its mission and scientific standards [3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects. The FBI noted that Goddard's lab contributed significantly to forensic science in the United States, and the Bureau learned much from the laboratory's work [3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects. Dean John Henry Wigmore of Northwestern's Law School also provided critical institutional support [3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects.

The SCDL was where Leonarde Keeler refined his portable polygraph instrument. It was where Fred Inbau conducted some of his most influential work on interrogation and forensic science — Inbau became the laboratory's director after the Chicago Police purchased the facility in 1938 for $25,000 [4]Verified A Method of Estimating the Accuracy of Individual Control Question Polygraph Tests
Proposed an innovative method for estimating individual test accuracy from physiological response magnitudes. The laboratory maintained close ties with Northwestern University Law School, and its researchers published regularly in law reviews and scientific journals [3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects.

Reid Arrives at the SCDL

John E. Reid (1910–1982) arrived at this institution as a member of the staff with extensive experience in lie-detection examination of criminal suspects and witnesses [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide[6]Verified Effect of the Stimulation Test Administered Before and After the First Relevant Chart of the Control Question Test
Confirms research on how stimulation test timing influences examinee psychological set in CQT examinations. His original 1947 paper, 'A Revised Questioning Technique in Lie-Detection Tests,' was published in the Journal of Criminal Law and Criminology [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide. Unlike many of his polygraph contemporaries, Reid had formal legal training — he was educated as an attorney and also worked as a former Chicago police officer [6]Verified Effect of the Stimulation Test Administered Before and After the First Relevant Chart of the Control Question Test
Confirms research on how stimulation test timing influences examinee psychological set in CQT examinations. He understood the evidentiary requirements of the courtroom and the critical importance of reducing both false-positive and false-negative errors.

The SCDL operated at the intersection of several intellectual traditions. The Chicago school of criminology emphasized empirical research and data-driven approaches. Northwestern's law school brought legal reasoning and evidentiary standards into the conversation. And the practical demands of working homicide, robbery, and fraud cases for the Chicago Police Department ensured any theoretical innovation would be immediately tested against real-world conditions.

Reid's legal training made him particularly sensitive to the concept of false positives. He recognized that the R/I test's structural inability to distinguish between fear-based arousal in innocent subjects and guilt-based arousal in deceptive subjects was producing exactly this kind of error at unacceptable rates. His 1947 innovation would establish the foundation for what the Reid firm and the broader profession would build upon for decades [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide. Learn more about Reid's full career in our profile of John E. Reid: Father of Polygraph Questioning.

From Observation to Hypothesis

The development of the control question concept did not happen in a single eureka moment. Reid's innovation emerged from systematic observation and extensive casework during the mid-1940s. By the time he formulated his new approach, he had conducted hundreds of polygraph examinations using the standard R/I format [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide.

Through this extensive experience, he developed a keen eye for patterns in polygraph charts that the R/I paradigm could not adequately explain. He noticed that some subjects later confirmed as truthful — through confessions by the actual perpetrator, independent evidence, or other corroboration — had produced R/I charts that looked deceptive. Conversely, some subjects later confirmed as deceptive had produced charts that were equivocal or even appeared truthful under the R/I interpretive framework.

These observations led Reid to a crucial insight: the problem was not with the polygraph instrument itself but with the question structure. The instrument was faithfully recording real physiological events. The issue was that examiners lacked a meaningful comparison standard within the test itself.

The Search for an Internal Baseline

Reid's key conceptual move was to ask: What if we could create a question that would cause a known, predictable emotional response in the subject — one that is substantial enough to be meaningful but is definitively unrelated to the crime under investigation? If such a question could be constructed, it would serve as an internal standard against which relevant-question responses could be measured.

This was a genuinely original idea in the context of 1940s forensic science. The notion of an internal control, borrowed in spirit from laboratory experimental design, had not previously been applied to polygraph testing. Reid was essentially proposing that each polygraph examination should contain its own built-in comparison condition, making the test self-calibrating for the individual subject's baseline reactivity [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide.

The logic worked as follows: if you ask a truthful person both a crime-relevant question and a carefully designed control question that provokes emotional concern, the truthful person should show a stronger response to the control question (which touches on a genuine personal concern) than to the relevant question (which references something they did not do). Conversely, a deceptive person should show a stronger response to the relevant question (which directly threatens their concealment effort) than to the control question.

This within-subject comparison model was the breakthrough that transformed polygraph from an absolute measurement into a relative measurement — arguably the single most important conceptual advance in polygraph history [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide. Understanding how this comparison works is essential for anyone preparing for a polygraph examination, as explained in our guide to what happens during the pre-test questionnaire.

Structural Deficiencies in the R/I Paradigm

To fully appreciate Reid's solution, it is worth examining the R/I test's weaknesses in detail. The Relevant/Irrelevant Test typically consisted of approximately ten to fifteen questions mixed in a predetermined order. Relevant questions addressed the crime directly: 'Did you steal the money from the safe?' Irrelevant questions were designed to be emotionally neutral: 'Is today Wednesday?'

The interpretive model assumed a simple dichotomy: significant responses to relevant questions indicated deception, while the absence of such responses indicated truthfulness. Reid's casework helped him identify several critical flaws:

The Innocence Problem: Innocent subjects often responded strongly to relevant questions simply because those questions were accusatory and emotionally charged. Being asked if you committed a murder while connected to a polygraph is inherently anxiety-provoking, regardless of guilt.

The Baseline Problem: Irrelevant questions were so emotionally flat that they provided no meaningful baseline for comparison. The physiological gap between 'Is today Wednesday?' and 'Did you kill your wife?' would be enormous for virtually anyone.

The Individual Differences Problem: People vary enormously in their baseline physiological reactivity. Some individuals are naturally hyperreactive; others are hypo-reactive. The R/I test had no mechanism for accounting for these individual differences.

The Habituation Problem: With repeated testing, subjects often habituated to the relevant questions, producing diminishing responses over successive chart runs, which could make a genuinely deceptive subject appear truthful.

The Post-War Demand for Better Methods

The post-World War II period was particularly important in driving improvement. The war had exposed American intelligence and military institutions to large-scale personnel screening challenges, revealing both the promise and limitations of existing methods. The emerging Cold War security environment was creating urgent demand for more reliable methods of determining trustworthiness.

Reid's work at the SCDL was situated at a moment when both the practical need for improved polygraph methodology and the intellectual resources to develop it were at their peak. The cumulative effect of the R/I test's flaws was a systematic tendency toward false positives — a finding already evident to careful practitioners. Reid understood that if polygraph was to gain broader acceptance in the legal and scientific communities, the testing methodology had to become more sophisticated than a simple comparison between emotionally loaded and emotionally empty questions.

For more on how polygraph testing expanded during this transformative period, see our article on polygraph in the 1960s: Warren Commission, Vietnam & Growth.

Designing the Comparison Question

In 1947, Reid published his landmark paper introducing what he called the 'comparative response' question and the 'guilt complex' question [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide[7]Verified Effects of Two Methods of Comparing Relevant and Control Questions on the Accuracy of Psychophysiological Detection of Deception
Foundational DoDPI research on comparison methods between relevant and control questions in CQT. His innovation centered on a new type of question initially called the 'control question' and later known more precisely as the 'comparison question' or 'probable lie comparison question.'

A control question had to meet several exacting criteria simultaneously. It needed to address a topic that was emotionally meaningful to the subject but clearly unrelated to the specific crime under investigation. It had to be broad enough that the subject would likely be uncertain about whether they could truthfully answer 'no.' It needed to cover a time period or behavioral domain that excluded the specific criminal act being investigated. And it had to be introduced during the pre-test interview in a way that maximized the subject's psychological investment in the question [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide.

A classic example of a comparison question might be: 'Before the age of 25, did you ever take something that did not belong to you?' This question is emotionally provocative (virtually everyone has committed some minor transgression), broadly worded (maximizing the likelihood that the subject cannot be entirely certain of their answer), and unrelated to the specific crime under investigation. The examiner would typically introduce this question during the pre-test phase in a manner suggesting that the answer is important to the overall evaluation.

The Psychological Logic of the CQT

The theoretical mechanism underlying the CQT is rooted in differential salience. For a truthful subject who did not commit the crime, the comparison question represents the greater psychological threat — it touches on real personal behavior about which the subject may feel genuinely uncertain or uncomfortable. The relevant question, by contrast, references an act the subject knows they did not commit.

For a deceptive subject who did commit the crime, the relevant question represents the far greater psychological threat — it directly addresses the act they are trying to conceal. The comparison question, while uncomfortable, pales in significance compared to the relevant question's direct threat to their concealment strategy.

This differential psychological salience produces different patterns of physiological responding that can be compared within the same individual's test session. The comparison is not between the subject and some external norm, but between two categories of questions answered by the same person under the same conditions. This is the critical improvement over the R/I test: the CQT provides its own internal control [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide.

Research has confirmed this approach works effectively across a range of conditions. A 1992 study by Honts, Raskin, and Kircher found no significant accuracy difference between control questions answered 'yes' versus 'no,' dispelling a widely held examiner belief that the answer format affected test validity [2]Verified Effectiveness of Control Questions Answered 'Yes': Dispelling a Polygraph Myth
Confirms that yes answers to control questions do not reduce CQT accuracy, dispelling a widely held examiner belief. A modified CQT study by MacLaren (1996) found that the test correctly identified 86% of guilty subjects and 83–89% of innocent subjects [8]Verified The Control Question Test in Polygraphic Examinations with Actual Controls for Truth
Demonstrates CQT diagnostic accuracy does not depend on deceptive answers to control questions; 86% guilty and 83-89% innocent correctly identified.

The Architecture of the First CQT

Reid's original test format positioned comparison questions strategically among relevant questions, creating a structured sequence that would maximize diagnostic clarity. The typical question sequence included irrelevant questions (to establish baseline physiological activity), relevant questions (directly addressing the crime), and comparison questions (addressing broader behavioral domains).

The format was revolutionary because it transformed the polygraph examination from a one-dimensional measurement (response vs. no response) into a two-dimensional comparison (response to relevant vs. response to comparison). This comparison model allowed examiners to account for individual differences in physiological reactivity — a problem the R/I test had never solved.

Reid's original design also incorporated the 'guilt complex' question — a question about a fictitious crime to which the subject's response could help distinguish between general anxiety and specific deception-related arousal. If a subject responded strongly to both the real crime questions and the fictional ones, the examiner could infer that the subject was generally anxious rather than specifically deceptive.

Research by Horvath and Palmatier (2008) later demonstrated that nonexclusive control questions achieved significantly higher accuracy rates — 85% for guilty subjects and 91% for innocent subjects — compared to exclusive time-bar control questions [9]Verified Effect of Two Types of Control Questions and Two Question Formats on the Outcomes of Polygraph Examinations
Confirms nonexclusive control questions achieved significantly higher accuracy (85% guilty, 91% innocent) than exclusive time-bar questions. This finding confirmed that the type and formulation of comparison questions significantly impacts test accuracy.

The Pre-Test Interview: Reid's Other Innovation

Reid also understood that the effectiveness of comparison questions depended critically on how they were introduced during the pre-test interview. The examiner's skill in framing comparison questions — making them seem important to the evaluation while simultaneously ensuring they are broad enough to provoke concern — was as important as the questions themselves.

This emphasis on the pre-test interview as a critical component of polygraph accuracy remains central to modern practice. Today's examiners spend considerable time crafting and introducing comparison questions, following principles Reid first articulated in 1947. The pre-test phase is where the psychological foundation of the entire examination is established. The importance of this phase is explored in detail in our guide to 5 things to know before a lie detector test.

Reid's emphasis on examiner skill also anticipated later research by Frank Horvath on inter-rater reliability. Horvath and Reid co-authored a landmark 1971 study, 'The Reliability of Polygraph Examiner Diagnosis of Truth and Deception,' which demonstrated that experienced examiners achieved an average of 91.4% correct judgments [9]Verified Effect of Two Types of Control Questions and Two Question Formats on the Outcomes of Polygraph Examinations
Confirms nonexclusive control questions achieved significantly higher accuracy (85% guilty, 91% innocent) than exclusive time-bar questions. This research confirmed that properly trained examiners could achieve high levels of consistency when evaluating CQT charts.

Cleve Backster and the Zone Comparison Technique

Among the most significant developments to emerge from Reid's foundational work was Cleve Backster's Zone Comparison Technique (ZCT), introduced in 1960. Backster was a former CIA interrogation specialist who founded the CIA's polygraph examination program in 1949 and became one of the most influential polygraph trainers in American history [1]Verified A Field Study of the Validity of the Directed Lie Control Question
First field validation of the directed-lie comparison question format, showing DLC at least as accurate as probable-lie CQT with fewer false positives.

After working at the CIA and later becoming director of the Keeler Polygraph Institute in Chicago, Backster founded what would become the Backster School of Lie Detection. His Zone Comparison Technique primarily involved an alteration of Reid's question sequencing and — critically — the introduction of a numerical scoring system for chart analysis. This quantification system standardized chart analysis, making it more objective and scientific than the clinical judgment approach that had previously dominated the field. Learn more about Backster's CIA career and polygraph legacy.

Backster's numerical scoring system was the first polygraph interpretation system to use standardized numerical evaluation and remains much in use today. The system assigns numerical values to the relative strength of physiological responses to relevant versus comparison questions, producing an overall score that determines whether the subject is classified as truthful, deceptive, or inconclusive.

Key Differences Between Reid and Backster Approaches

While both Reid and Backster built on the same comparison question foundation, their approaches diverged in important ways. Reid's original format placed greater emphasis on clinical examiner judgment, while Backster moved toward greater standardization and objectivity through numerical scoring.

Reid retained the 'guilt complex' question in his format, while Backster's ZCT introduced 'symptomatic' questions designed to detect outside issues that might be contaminating the test results. The two approaches also differed in question sequencing, the number of charts collected, and the relative weighting given to different physiological channels.

These differences spawned a productive tension within the polygraph profession that continues to drive methodological refinement. Modern federal polygraph practice, as standardized through the Department of Defense Polygraph Institute (DoDPI) and its successors, draws on both traditions. The Air Force Modified General Question Test (AFMGQT), for example, represents a synthesis of elements from both the Reid and Backster traditions.

The question of which approach is superior has been addressed by research including a study by Shull and Crowe (1993) at DoDPI, which examined two methods of comparing relevant and control question responses and found differences in accuracy outcomes [7]Verified Effects of Two Methods of Comparing Relevant and Control Questions on the Accuracy of Psychophysiological Detection of Deception
Foundational DoDPI research on comparison methods between relevant and control questions in CQT. These findings contributed to the ongoing refinement of CQT methodology.

Meta-Analyses and Accuracy Research

The CQT has been subjected to extensive scientific scrutiny since Reid's original innovation. A 2021 comprehensive meta-analysis by Honts et al. captured data from 138 datasets and found that CQT outcomes generally produced accuracy estimates of over 85% [3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects. The study found significant moderator effects, notably that motivation level had a positive linear relationship with accuracy measures. Information Gain analysis of CQT outcomes showed a significant information increase over interpersonal deception detection across almost the complete range of base rates.

An earlier meta-analysis by Kircher, Horowitz, and Raskin (1988) examined 14 CQT laboratory studies and found accuracy exceeding 85% with significant moderator effects including the type of participants and motivation levels [3]Verified Meta-Analysis of Mock Crime Studies of the Control Question Polygraph Technique
Meta-analysis of 14 CQT laboratory studies finding accuracy exceeding 85% with significant moderator effects. The National Research Council's 2003 review, which included 37 laboratory studies and 7 field studies, estimated the median accuracy of the CQT at.85 — confirming that the technique performs well above chance.

Gordon Barland (1985) proposed an innovative method for estimating the accuracy of individual polygraph tests from the magnitude of physiological responses, laying the groundwork for confidence-based polygraph decision reporting [4]Verified A Method of Estimating the Accuracy of Individual Control Question Polygraph Tests
Proposed an innovative method for estimating individual test accuracy from physiological response magnitudes. This approach allowed examiners to express not just a categorical verdict but a degree of confidence in that verdict.

A field study by Honts and Raskin (1988) provided the first field validation of the directed-lie comparison question format, showing that directed-lie comparisons were at least as accurate as probable-lie CQT with fewer false positive errors [1]Verified A Field Study of the Validity of the Directed Lie Control Question
First field validation of the directed-lie comparison question format, showing DLC at least as accurate as probable-lie CQT with fewer false positives. This finding opened up new possibilities for improving the CQT's protection of innocent subjects.

The 1983 OTA Report and Federal Scrutiny

The 1983 Office of Technology Assessment (OTA) report to the U.S. Congress examined the scientific evidence for polygraph testing and represented one of the most significant governmental reviews of polygraph validity. The OTA report concluded that while polygraph testing detected deception better than chance, significant error rates were possible and examiner differences could affect validity.

The OTA report contributed to the passage of the Employee Polygraph Protection Act of 1988, which restricted private-sector polygraph use but explicitly exempted government agencies. This legislation paradoxically strengthened polygraph testing in the federal sector by eliminating many low-quality private screening applications while preserving the use of well-administered CQT examinations in criminal investigation and national security contexts.

For more on governmental scrutiny of polygraph testing, see our article on The Church Committee & Polygraph Oversight: 1975–1976. Understanding the legal landscape helps contextualize why methods to beat a lie detector test don't actually work — because properly administered CQT examinations are designed to be robust against simple countermeasures.

The Stimulation Test and Psychological Set

An important refinement to CQT practice concerns the stimulation test (or 'stim test'), which is often administered during a polygraph examination to demonstrate the instrument's sensitivity. Research by James Allan Matte (2012) examined how the timing of the stimulation test — whether administered before or after the first relevant chart — influences the examinee's psychological set and physiological response patterns [6]Verified Effect of the Stimulation Test Administered Before and After the First Relevant Chart of the Control Question Test
Confirms research on how stimulation test timing influences examinee psychological set in CQT examinations.

This research confirmed that the stimulation test plays an important role in establishing the examinee's belief in the test's accuracy, which in turn influences the differential responding that makes the CQT effective. Deceptive subjects who believe the instrument can detect their lies show stronger relevant-question responses, while truthful subjects who believe in the test show stronger comparison-question responses. The stimulation test thus reinforces the psychological conditions that make the CQT's comparison model work effectively.

DoDPI and the Professionalization of Federal Polygraph

The Department of Defense's efforts to standardize polygraph practice represent one of the most significant institutional legacies of Reid's CQT innovation. The U.S. Army Polygraph School was established in 1951 at Fort Gordon, Georgia. In November 1986, the school was redesignated as the Department of Defense Polygraph Institute (DoDPI), and a September 1991 revision of DoD Directive 5210.78 placed the institute under the authority of the Assistant Secretary of Defense for Command, Control, Communications, and Intelligence.

DoDPI trains all federal polygraph examiners, promoting standardization across agencies and eliminating unnecessary duplicate examinations. The institute conducts ongoing evaluations of CQT validity and researches new techniques, instrumentation, and analytical methods. In Fiscal Year 1998, the Department published a handbook for all federal polygraph examiners standardizing techniques and procedures for conducting polygraph examinations.

In January 2007, DoDPI was renamed the Defense Academy for Credibility Assessment (DACA), and in August 2010 it was redesignated the National Center for Credibility Assessment (NCCA), reflecting a broadening mission to encompass all credibility assessment technologies. Throughout these organizational changes, the CQT has remained the foundational testing format for federal polygraph examinations.

For those interested in pursuing a career in this field, visit our become a polygraph examiner page or explore polygraph training options, including our guide to polygraph training in Georgia.

Modern Research and Continuing Refinement

Raymond Nelson, a prominent researcher affiliated with the Lafayette Instrument Company and the American Polygraph Association, has contributed extensively to the modern understanding of comparison question testing. His work on question formulation, test data analysis, and empirical scoring systems has helped refine the theoretical and practical foundations of CQT examination. Nelson, Krapohl, and Handler (2008) developed an empirically based manual scoring system that demonstrated inexperienced examiners could produce blind-scoring polygraph data with decision accuracy and inter-rater reliability rates equivalent to experienced examiners.

Research continues to validate and refine the CQT approach. A study on polygraph testimony and juror judgments by Myers and Arbuthnot (1997) found that jurors rated both CQT and GKT polygraph testimony below other forms of evidence such as eyewitness testimony, highlighting the importance of continuing to strengthen the scientific foundation of polygraph testing [10]Verified Polygraph Testimony and Juror Judgments: A Comparison of the Guilty Knowledge Test and the Control Question Test
Found no differences among conditions for jury verdicts; jurors rated both CQT and GKT polygraph testimony below eyewitness testimony.

The work of Benjamin Burack on psychometrics and polygraph standardization also contributed to the scientific maturation of the field, establishing measurement standards that continue to influence how polygraph data is collected and analyzed today.

The CQT as the Global Standard

More than seven decades after Reid published his landmark paper, the Control Question Technique remains the most widely used polygraph format worldwide [5]Verified The Control Question Test
Confirms Reid invented the CQT in 1947, the most widely used polygraph method worldwide. Every major polygraph testing format in current use — from the Backster Zone Comparison Technique to the Air Force Modified General Question Test to the various federal screening protocols — is built upon the within-subject comparison model that Reid first proposed in 1947.

The CQT has been adapted for use in criminal investigation, pre-employment screening, national security vetting, and post-conviction sex offender testing (PCSOT). Each application has required modifications to Reid's original format, but the core principle — comparing physiological responses to relevant questions against responses to carefully constructed comparison questions — remains unchanged.

Reid's innovation also sparked the development of alternative comparison question formats, including the directed-lie comparison question validated by Honts and Raskin (1988) [1]Verified A Field Study of the Validity of the Directed Lie Control Question
First field validation of the directed-lie comparison question format, showing DLC at least as accurate as probable-lie CQT with fewer false positives. The directed-lie approach, in which the examiner instructs the subject to answer a known lie, offers advantages in standardization and has been shown to produce at least comparable accuracy with fewer false positive errors.

Polygraph testing has evolved significantly since 1947 — from analog instruments to computerized systems, from clinical judgment to numerical scoring algorithms — but the fundamental architecture of the modern polygraph examination remains Reid's comparison question model. For anyone seeking a polygraph examination today, understanding this history provides valuable context for what to expect during testing.

The Ongoing Evolution of CQT Science

Reid's 1947 invention was not the end of the story but the beginning of a continuing scientific enterprise. The Concealed Information Test (CIT), originally called the Guilty Knowledge Test (GKT) when developed by David Lykken in 1959, represents an alternative paradigm that emerged partly in response to the CQT's theoretical assumptions. While the CIT has strong support from the academic research community, the CQT remains the dominant format in applied forensic testing worldwide, a testament to the practical effectiveness of Reid's comparison question concept.

The question of why a polygraph test may not always be accurate is one that the profession continues to address through research and methodological improvement. Factors including examiner training, question formulation, subject suitability, and environmental conditions all influence test outcomes — areas where pregnancy and other physiological states may be relevant considerations.

The history of polygraph testing in the civil rights era and across Scandinavia further illustrates how Reid's innovation has been adapted across cultural and legal contexts. Each adaptation reinforces the versatility and enduring value of the comparison question approach.

To explore our full database of peer-reviewed research on polygraph testing, visit the Polygraph Research Database. To book a professional polygraph examination, visit our booking page or check polygraph test locations and pricing near you.