What Is a Polygraph Retest? When & Why Tests Are Repeated

Defining the Polygraph Retest

A polygraph retest is a subsequent polygraph examination conducted on the same issue, topic, or set of relevant questions that was addressed in a prior examination. Unlike a casual repeat, a polygraph retest is a formal procedure governed by professional standards — most notably those published by the American Polygraph Association (APA) — and is typically prompted by a specific, documentable reason that calls the original examination's validity, completeness, or reliability into question [1]Verified American Polygraph Association — Polygraph Frequently Asked Questions
Confirms APA position on inconclusive results and polygraph screening practices among U.S. police agencies.

The APA, established in 1966, is the world's leading association dedicated to evidence-based credibility assessment and promotes the highest standards for its 2,700+ members [1]Verified American Polygraph Association — Polygraph Frequently Asked Questions
Confirms APA position on inconclusive results and polygraph screening practices among U.S. police agencies. The retest is not simply a matter of reattaching sensors and asking the same questions again. It represents a complete, independent examination that may involve a different examiner, a different validated polygraph technique, updated question formulation, and entirely new chart collection. The goal is to produce an independent diagnostic opinion that either confirms, refutes, or clarifies the findings of the original examination.

Retests arise across every domain where polygraph testing is used: private consumer tests, criminal defense, pre-employment screening for law enforcement and intelligence agencies, post-conviction sex offender testing (PCSOT), and therapeutic settings. Understanding when a retest is appropriate — and when it is not — is essential for consumers, legal professionals, and examiners alike.

Why Retests Exist in Professional Polygraph Practice

Polygraph testing is a psychophysiological process that depends on the interplay between human physiology, psychological state, environmental conditions, examiner skill, and instrument reliability. The autonomic nervous system drives the physiological responses measured during testing, and given this complexity, there are legitimate circumstances where a single examination cannot produce a definitive result [2]Verified Autonomic Nervous System & Polygraph: How ANS Powers Testing
Explains the physiological foundations underlying polygraph responses and why medical conditions affect testing.

The APA's Standards of Practice recognize that no single polygraph examination is infallible. The APA's 2011 meta-analysis of 38 qualifying studies — covering 3,723 examinations scored by 295 independent scorers — confirmed that even the best validated techniques produce an estimated inconclusive rate of approximately 11–13% [3]Verified APA Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms inconclusive rates of 11% for single-issue testing and 13% across all validated PDD techniques based on 3,723 examinations. The very existence of inconclusive result protocols and peer review mechanisms demonstrates the profession's acknowledgment that retesting is sometimes necessary and appropriate.

The pretest interview itself plays a critical role in establishing conditions for accurate data collection. Research by Reutskaya (2016) reconceptualizes the pretest interview as a semi-formalized directional diagnostic interview that functions as the experimental introduction to the polygraph procedure [4]Verified Theoretical basis of pretest interview the survey on a polygraph
Proposes reconceptualizing the pretest interview as a semi-formalized directional diagnostic interview functioning as the experimental introduction to polygraph. When this foundation is compromised for any reason, a retest may be the appropriate path forward.

Are 'Retest' and 'Retake' the Same Thing?

In everyday conversation, 'retest' and 'retake' are often used interchangeably, but within professional polygraph practice, they carry different connotations. A retake typically refers to a second examination following an inconclusive result — the original exam produced no diagnostic opinion, and another attempt is made to obtain one. A retest is a broader term that encompasses any repeated examination regardless of the reason, including scenarios where a definitive result was obtained but is being challenged, reviewed, or repeated for quality control purposes.

For the purposes of this guide, we use 'retest' as the comprehensive term covering all circumstances in which a polygraph examination is repeated. If you received an inconclusive result and want specific guidance, our detailed article on inconclusive polygraph results and APA standards provides focused information on that particular trigger.

Key Terminology You Should Know

Inconclusive (INC) — The original exam produced data that could not be scored as either Deception Indicated (DI) or No Deception Indicated (NDI). According to the APA's meta-analytic survey, inconclusive results occur in approximately 11% of single-issue diagnostic examinations and 13% across all validated PDD techniques [3]Verified APA Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms inconclusive rates of 11% for single-issue testing and 13% across all validated PDD techniques based on 3,723 examinations.

No Opinion (NO) — Similar to inconclusive, but often used when the examiner determines that conditions prevented valid data collection entirely. The APA Standards of Practice recognize this as a distinct result category alongside DI, NDI, and INC [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories.

Invalid Examination — The test is declared void due to equipment failure, procedural violation, or other compromising factor. No result is reported.

Peer Review — An independent quality review of the original examination's charts, scoring, and procedures by a second qualified examiner.

Second Opinion Examination — A retest specifically arranged to provide an independent assessment, often requested by an attorney or examinee.

When Technology Fails Mid-Examination

Modern polygraph instruments are sophisticated computerized systems that simultaneously record multiple physiological channels — typically thoracic and abdominal respiratory activity (recorded separately via pneumograph components), electrodermal activity (EDA), cardiovascular activity, and often a seat activity sensor [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories. Leading platforms include Lafayette Instrument's LXSoftware and LXEdge (compatible with the LX6 and LX7 systems) and Stoelting's CPSpro Fusion software [6]Verified LXEdge — Lafayette Instrument Company
Confirms LXEdge is a real polygraph software platform compatible with Lafayette LX6 and LX7 systems[7]Verified CPSpro Fusion Software — Stoelting Company
Confirms CPSpro Fusion is a real polygraph software platform manufactured by Stoelting Company since 1930. When any component of these systems fails during data collection, the integrity of the entire examination can be compromised.

Equipment-related reasons for retesting include sensor malfunction (a pneumograph tube develops a leak, an EDA electrode loses contact, or a blood pressure cuff fails to maintain proper inflation), software crashes or data corruption, power interruption during field examinations, and calibration failure. ASTM International has published specific standards governing polygraph instrument calibration and functionality checks, including Standard E2063 for calibration and functionality checks used in forensic PDD examinations [8]Verified ASTM E2063 Standard Practice for Calibration and Functionality Checks Used in Forensic PDD Examinations
Confirms ASTM International publishes standards for polygraph instrument calibration under Committee E52.

For a deeper understanding of instrument specifications and manufacturer support policies, see our polygraph equipment warranty and support comparison guide.

When equipment failure occurs, the retesting timeline is typically shorter than standard waiting periods, because no valid physiological data was obtained from the original session. The examinee was not meaningfully 'tested' on the relevant issues, so concerns about test-retest sensitization are minimal. In most cases, the retest can be scheduled within days or weeks of the original failed session.

How Examiners Should Handle Equipment Failure

Professional examiners are expected to follow specific protocols when equipment malfunctions occur. APA Standards of Practice require that examiners use evidence-based validated testing techniques and maintain proper instrumentation [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories. When failure occurs despite these precautions, the examiner should immediately inform the examinee that a technical issue has occurred, document the nature and timing of the malfunction in the examination file, determine whether any usable chart data was collected prior to the failure, and make a professional judgment about whether to attempt to resume testing in the same session or reschedule entirely.

The examination should be classified as 'invalid' or 'incomplete' in the official report — not as inconclusive, deceptive, or non-deceptive. Examinees who experience equipment failure should not be charged for a retest caused by the examiner's equipment. Reputable polygraph service providers will reschedule at no additional cost when the failure was equipment-related. For more on examiner responsibilities and potential liability issues, see our guide on malpractice and liability risks for polygraph examiners.

How Illness Compromises Polygraph Data

A polygraph measures involuntary physiological responses — breathing patterns, sweat gland activity, blood pressure changes, and pulse rate variations. The psychophysiological basis of testing depends on the examiner's ability to distinguish specific responses to relevant questions from general physiological noise. Any medical condition that alters baseline physiological functions can contaminate the data.

Common medical scenarios that may prompt a retest include respiratory infections (colds, flu, bronchitis, or COVID-19 can significantly alter breathing patterns), fever (which affects cardiovascular output and can increase electrodermal activity globally), gastrointestinal distress, acute pain, and medication effects — particularly those altering cardiovascular function or suppressing nervous system activity.

Responsible examiners conduct a thorough pre-test health assessment. The APA Standards of Practice require that the examiner make reasonable efforts to determine that the examinee is a suitable candidate for polygraph testing, including basic inquiries into medical and psychological conditions [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories. The key principle is simple: if illness is producing physiological noise that compromises the examiner's ability to distinguish relevant from comparison responses, the examination should be postponed.

Chronic Conditions vs. Acute Illness

It is important to distinguish between temporary illness (which warrants postponement and retest) and chronic conditions that an examinee manages daily. Conditions such as controlled heart conditions, well-managed diabetes, or treated anxiety disorders do not automatically disqualify someone from being tested. An experienced examiner can accommodate stable chronic conditions by adjusting sensitivity settings, extending the pre-test period, or selecting techniques that are less affected by the specific condition.

A retest is warranted only when an acute change — a flare-up, an uncontrolled episode, or a new medication adjustment — temporarily pushes the examinee outside the range of testable physiological function. Understanding the role of memory in polygraph testing also helps explain why certain cognitive or neurological conditions require special consideration during retesting.

Why Polygraph Exams Produce Inconclusive Results

An inconclusive result means the polygraph data did not meet the threshold for either a Deception Indicated (DI) or No Deception Indicated (NDI) finding. The APA's comprehensive 2011 meta-analysis — covering 3,723 examinations across 38 studies — found that single-issue diagnostic techniques produced an inconclusive rate of 11%, while multi-issue techniques produced an inconclusive rate of 13%, with an overall rate of 13% across all validated PDD techniques [3]Verified APA Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms inconclusive rates of 11% for single-issue testing and 13% across all validated PDD techniques based on 3,723 examinations. This makes inconclusive results the single most common reason for retesting.

Inconclusive outcomes occur for various reasons: genuine physiological ambiguity where the examinee's responses to both relevant and comparison questions are of similar magnitude, test anxiety that elevates responses uniformly, outside-issue concerns that generate competing physiological responses, suboptimal question formulation, and partial countermeasure attempts that produce unscoreable data. Research on how polygraph questions are formulated and reviewed is covered in our guide on how polygraph questions are reviewed before the test.

When an inconclusive result occurs, the APA Standards of Practice provide the examiner with several options: reporting the result as inconclusive, extending the current session with additional chart collections, or recommending a retest at a later date [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories. The decision depends on the examiner's professional judgment, the context of the examination, and the examinee's state at the time.

Retest Timing After Inconclusive Results

For inconclusive results, best practice recommends a meaningful waiting period before retesting on the same issue. The British Polygraph Society recommends that a person should not be tested more than 2 times in a 12-month period for best results, and not more than 4 times per year under any circumstances [9]Verified British Polygraph Society FAQ
Confirms recommendation to not test more than 2 times in 12 months and not more than 4 times per year; confirms attorney-client privilege for defense-arranged tests. This interval serves multiple purposes: it allows the examinee's test-related anxiety to subside, reduces the possibility of test-retest sensitization, and provides time for any temporary conditions to resolve.

Research strongly supports caution with repeated testing. A landmark study by Balloun and Holmes (1979) found that detection accuracy vanished entirely on the second examination in a laboratory setting, indicating that repeated polygraph testing may reduce diagnostic effectiveness when the examinee becomes familiar with the procedure [10]Verified Effects of Repeated Examinations on the Ability to Detect Guilt with a Polygraphic Examination: A Laboratory Experiment with a Real Crime
Found that electrodermal activity was the only effective measure across repeated tests; detection accuracy vanished on the second examination. However, Lieblich et al. (1974) found that combining GSR responses across multiple repetitions actually reduced detection errors, suggesting that the relationship between repetition and accuracy is nuanced [11]Verified Efficiency of GSR detection of information with repeated presentation of series of stimuli in two motivational states
Found that combining GSR responses across 10 repetitions reduced detection errors; motivation level had no noticeable effect on detection efficiency.

These findings are consistent with research by Hu (2012), which demonstrated that extensive training with intentional practice can erase the reaction-time gap between lying and truth-telling, underscoring the importance of adequate spacing between examinations [12]Verified A repeated lie becomes a truth? The effect of intentional control and training on deception
Demonstrated that training with intentional practice fully erased the reaction-time gap between lying and truth-telling, supporting adequate spacing between retest examinations. In contexts where time is critical — such as criminal defense preparation or employment deadlines — shorter intervals may be justified if the retesting examiner documents the rationale.

What Is Polygraph Peer Review?

Peer review is one of the most important quality-assurance mechanisms in professional polygraph practice. It involves an independent, qualified examiner reviewing the complete examination file — including the pre-test interview documentation, question formulation, chart data, scoring worksheets, and the examiner's diagnostic opinion — to assess whether the examination was conducted in accordance with APA standards and whether the scoring and conclusions are supported by the physiological data.

ASTM International published Standard E2031, Standard Practice for Quality Control of Psychophysiological Detection of Deception (PDD) Examinations, which establishes essential procedures for quality control review [13]Verified ASTM E2031 Standard Practice for Quality Control of Psychophysiological Detection of Deception (PDD) Examinations
Confirms ASTM established quality control standards for PDD examinations requiring experienced examiners trained in the utilized PDD format. This standard specifies that experienced examiners trained in the PDD format used by the original examiner are qualified to conduct quality control reviews. Federal polygraph programs, including CBP's, are required to comply with NCCA (National Center for Credibility Assessment) quality control standards [14]Verified DHS OIG Report: Most Complaints about CBP's Polygraph Program Are Ambiguous or Unfounded (OIG-18-68)
Confirms CBP's 2-year waiting period for failed polygraphs, quality control program compliance with NCCA standards, and that at least two examiners independently agree on results.

For a deeper understanding of the peer review process and how it works in practice, explore our guide on spot analysis in polygraph chart marking and scoring.

When Peer Review Leads to Retesting

A peer reviewer may recommend retesting in the following circumstances: scoring disagreement where the reviewer rescores charts and arrives at a different diagnostic opinion, question formulation errors that rendered data unreliable, procedural violations that affected the examination's validity, technique compliance issues, and artifact concerns involving unaddressed movement artifacts, respiratory anomalies, or EDA irregularities.

The distinction between global evaluation and numerical scoring becomes especially important during peer review. If the original examiner relied on global evaluation while the reviewer's numerical scoring produces a different result, a retest with a third, independent examiner may be the most appropriate resolution.

When a peer review results in a retest recommendation, the retest should ideally be conducted by a different examiner than either the original examiner or the peer reviewer, to ensure maximum independence and objectivity. This principle is consistent with research methodology standards in the polygraph field, as discussed in our guide to scientific studies in polygraph research.

Defense Attorneys and Strategic Retesting

One of the most common contexts for polygraph retesting is legal defense. Defense attorneys frequently arrange independent polygraph examinations for their clients, particularly when the client failed a law-enforcement-administered polygraph during an investigation, when original polygraph results are being used as leverage in plea negotiations, when the attorney suspects procedural irregularities in the original examination, or when a favorable polygraph result could support the client's credibility.

A key principle is that defense-arranged retests are conducted under attorney-client privilege, meaning the results remain confidential unless the attorney chooses to disclose them [9]Verified British Polygraph Society FAQ
Confirms recommendation to not test more than 2 times in 12 months and not more than 4 times per year; confirms attorney-client privilege for defense-arranged tests. This creates a strategically valuable scenario for the defense: if the retest confirms deception, the results stay private; if it supports the client's truthfulness, the attorney can share the findings strategically. For more on this topic, see our analysis of The Jinx and Robert Durst: deception, polygraph, and media analysis.

Research by Granhag and Strömwall (2002) on repeated interrogations found that, contrary to conventional wisdom, truthful and deceptive statements were equally consistent across repeated tellings, which has important implications for how retest results should be interpreted compared to originals [15]Verified Repeated interrogations: Verbal and non-verbal cues to deception
Found that truthful and deceptive statements were equally consistent across repeated interrogations, with behavioral differences increasing over time.

Challenging Polygraph Results in Court Proceedings

While polygraph admissibility varies by jurisdiction, the ability to challenge original findings remains important even where results are not directly presented to a jury. Attorneys may use independent retest results to persuade prosecutors to reduce charges, support motions to suppress statements made following a polygraph examination, demonstrate credibility during sentencing hearings, or counter polygraph evidence presented in Daubert or Frye hearings.

The concern about false confessions is particularly relevant here — polygraph results can sometimes trigger confessions that may not be reliable, and a retest by an independent examiner can help expose such situations.

When arranging a legal retest, attorneys should select an examiner who graduated from an APA-approved school, uses validated techniques, and has experience providing expert testimony. The examination should be documented thoroughly, as the retest report may need to withstand scrutiny from opposing counsel and the court.

Prosecution-Requested Retests

Retests are not exclusively a defense tool. Prosecutors may request retesting when original examination results are inconclusive or when they want additional confirmation before proceeding with or dropping charges. In some jurisdictions, courts may order retesting as part of pre-trial proceedings or as a condition of probation.

Under SEAD 4 (Security Executive Agent Directive 4), no adverse action may be taken solely on the basis of polygraph examination results in the absence of adjudicatively significant information [16]Verified Next Steps After an Inconclusive or Failed Polygraph — ClearanceJobs
Confirms SEAD 4 provision that no adverse action may be taken solely on the basis of polygraph examination technical calls without adjudicatively significant information. This regulatory framework means that inconclusive or deceptive results alone cannot determine an outcome — creating inherent value in retesting to clarify ambiguous findings.

When the Examiner Gets It Wrong

Human error is an unavoidable reality in any assessment process, and polygraph testing is no exception. Examiner errors that may warrant retesting include incorrect technique implementation, inadequate pre-test interviews, failure to properly review all test questions with the examinee prior to chart recording (which is required by APA Standards of Practice Section 1.6.3) [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories, and improper scoring methodology.

The APA requires that member examiners use evidence-based validated testing techniques, and techniques must meet specific accuracy thresholds: evidentiary techniques require at least 90% accuracy excluding inconclusives, while investigative techniques require at least 80% [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories. When an examiner uses unvalidated techniques or deviates from validated protocols without documenting the reasons, the resulting examination may be vulnerable to challenge.

For a comprehensive overview of the varieties of polygraph examinations — including counterintelligence, lifestyle, and full-scope formats — understanding the correct protocol for each type helps identify when deviations have occurred.

Protecting Against Examiner Error

APA Standards of Practice require examinations to be scheduled for not less than 90 minutes, and a member examiner shall not conduct more than five examinations of any type in one day [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories. These requirements exist specifically to prevent fatigue-related errors and ensure adequate time for proper pre-test preparation, chart collection, and scoring.

All polygraph reports, test questions, data, recordings, and documents related to all phases of the exam must be maintained for a minimum of three years [5]Verified APA Standards of Practice (Amended August 23, 2024)
Confirms APA requirements for validated techniques, 90-minute minimum exam duration, 5-exam daily limit, documentation retention, and result reporting categories. This documentation requirement ensures that retesting decisions can be informed by a complete understanding of what occurred during the original examination. For more on how examiner quality and oversight affects outcomes, see our article on polygraph limitations in technology, science, and legal contexts.

How PCSOT Retesting Works

Post-Conviction Sex Offender Testing (PCSOT) represents a unique retesting context. In PCSOT programs, offenders on probation or parole undergo periodic maintenance polygraph examinations. According to the APA's Model Policy for Post-Conviction Sex Offender Testing (2021), maintenance examinations should prioritize investigation of the examinee's honesty and compliance during recent months, generally not exceeding one year [17]Verified APA Model Policy for Post-Conviction Sex Offender Testing (September 2021)
Confirms four basic PCSOT examination types, multidisciplinary collaboration requirements, and testing procedure standards.

PCSOT practitioners recommend that maintenance examinations be administered every six months but no longer than every 12 months [18]Verified PCSOT Maintenance Examination Frequency Guidelines
Confirms recommendation that maintenance examinations be administered every six months but no longer than every 12 months. PCSOT examiners use four basic types of examinations: instant offense exams, sexual history disclosure exams, maintenance exams, and sexual offense monitoring exams [17]Verified APA Model Policy for Post-Conviction Sex Offender Testing (September 2021)
Confirms four basic PCSOT examination types, multidisciplinary collaboration requirements, and testing procedure standards. Examiners engaging in PCSOT activities must complete specialized training — typically a 40-hour APA-accredited PCSOT course [9]Verified British Polygraph Society FAQ
Confirms recommendation to not test more than 2 times in 12 months and not more than 4 times per year; confirms attorney-client privilege for defense-arranged tests — and should adhere to all generally accepted polygraph testing protocols and validated principles [17]Verified APA Model Policy for Post-Conviction Sex Offender Testing (September 2021)
Confirms four basic PCSOT examination types, multidisciplinary collaboration requirements, and testing procedure standards.

ASTM International also published Standard E2080, a Guide for Clinical Psychophysiological Detection of Deception Examinations for Sex Offenders, which directs that examiners for this application be specifically trained in issues associated with supervision and treatment of sex offenders [19]Verified ASTM E2080 Standard Guide for Clinical PDD Examinations for Sex Offenders
Confirms ASTM standard for clinical polygraph examinations for sex offenders requiring specialized examiner training. For broader context on how polygraph has been integrated into sex offender management in the United Kingdom, see our history of polygraph in the UK.

Retesting After Failed PCSOT Examinations

When a PCSOT maintenance or monitoring exam produces a Deception Indicated result, the containment team — comprising the polygraph examiner, treatment provider, and supervising officer — collaborates to determine appropriate next steps. A follow-up single-issue examination may be used when a maintenance exam produces unresolved results [17]Verified APA Model Policy for Post-Conviction Sex Offender Testing (September 2021)
Confirms four basic PCSOT examination types, multidisciplinary collaboration requirements, and testing procedure standards.

The results of maintenance examinations are used by probation and parole officers to develop supervision strategies and by treatment providers to modify individual treatment plans and assess risk [17]Verified APA Model Policy for Post-Conviction Sex Offender Testing (September 2021)
Confirms four basic PCSOT examination types, multidisciplinary collaboration requirements, and testing procedure standards. Retesting in this context serves a clinical purpose alongside its assessment function, consistent with the broader goals of increasing public safety through incremental validity in risk-assessment decisions [17]Verified APA Model Policy for Post-Conviction Sex Offender Testing (September 2021)
Confirms four basic PCSOT examination types, multidisciplinary collaboration requirements, and testing procedure standards.

Federal Agency Retest Policies

Pre-employment polygraph retesting policies vary significantly across federal agencies. At U.S. Customs and Border Protection (CBP), polygraph examination results are valid for a two-year period, and applicants who fail can retake the exam after that two-year waiting period [20]Verified U.S. Customs and Border Protection — Polygraph Careers Page
Confirms polygraph examination results are valid for a two-year period at CBP and applicants are eligible to retake after that period. If a test is inconclusive, CBP may invite the applicant to retake the exam sooner [14]Verified DHS OIG Report: Most Complaints about CBP's Polygraph Program Are Ambiguous or Unfounded (OIG-18-68)
Confirms CBP's 2-year waiting period for failed polygraphs, quality control program compliance with NCCA standards, and that at least two examiners independently agree on results. The DHS Office of Inspector General confirmed that CBP does not consider a polygraph final until quality control personnel review, concur with, and certify the examiner's results [14]Verified DHS OIG Report: Most Complaints about CBP's Polygraph Program Are Ambiguous or Unfounded (OIG-18-68)
Confirms CBP's 2-year waiting period for failed polygraphs, quality control program compliance with NCCA standards, and that at least two examiners independently agree on results.

For agencies requiring TS/SCI (Top Secret/Sensitive Compartmented Information) clearances, the process can involve multiple polygraph sessions. Some federal agencies and clearances require 4 or 5 polygraph examinations before candidates pass, especially for SCI access [21]Verified How to Handle a Failed Polygraph Test: Expert Guide — Axeligence
Confirms some federal agencies require 4 or 5 polygraph examinations before candidates pass for SCI access. Inconclusive results are relatively common in these high-stakes screenings. Importantly, SEAD 4 regulations prohibit clearance denials based solely on polygraph results without additional supporting evidence [16]Verified Next Steps After an Inconclusive or Failed Polygraph — ClearanceJobs
Confirms SEAD 4 provision that no adverse action may be taken solely on the basis of polygraph examination technical calls without adjudicatively significant information.

For a complete overview of the different types of polygraph exams used in federal hiring, see our guide to CI, lifestyle, and full-scope polygraph examinations.

Law Enforcement Pre-Employment Retesting

For state and local law enforcement pre-employment polygraph testing, the Employee Polygraph Protection Act (EPPA) of 1988 does not apply to government agencies [22]Verified Employee Polygraph Protection Act of 1988 (EPPA)
Confirms EPPA prohibits most private employers from using polygraph tests, with exemptions for government employers and certain security-related private industries. This means local, state, and federal government employers — including police departments — are exempt from EPPA restrictions [22]Verified Employee Polygraph Protection Act of 1988 (EPPA)
Confirms EPPA prohibits most private employers from using polygraph tests, with exemptions for government employers and certain security-related private industries.

In Washington State, for example, polygraph reports older than six months are considered invalid for law enforcement hiring purposes [23]Verified WAC 139-07-040: Washington State Polygraph Assessment Standards
Confirms polygraph reports older than six months are considered invalid for Washington State law enforcement hiring purposes. Many agencies offer a second chance to take the pre-employment polygraph test, which could be scheduled for the following week, several weeks later, or even up to six months later, depending on agency policy [24]Verified Your Guide to Inconclusive Pre-Employment Polygraph Results
Confirms agencies offer retest opportunities for inconclusive results and that an inconclusive result is not the examinee's fault. The APA conducts research indicating that among surveyed large police agencies, 62% had an active polygraph screening program [1]Verified American Polygraph Association — Polygraph Frequently Asked Questions
Confirms APA position on inconclusive results and polygraph screening practices among U.S. police agencies.

Candidates who receive an inconclusive result should understand that this outcome is not their fault and does not automatically disqualify them [24]Verified Your Guide to Inconclusive Pre-Employment Polygraph Results
Confirms agencies offer retest opportunities for inconclusive results and that an inconclusive result is not the examinee's fault. For more information on what disqualification actually means, see our guide on polygraph examination disqualification.

Procedural Differences from the Original Examination

A properly conducted retest is not a simple repeat of the original examination. Key procedural differences include a fresh pre-test interview conducted by the retesting examiner, potentially different question formulation to address identified weaknesses, possibly a different validated technique (for example, switching from a multi-issue screening format to a single-issue diagnostic format for greater precision), entirely new chart collection and independent scoring, and often a different examiner to ensure objectivity.

The retesting examiner should review the original examination file — including charts, scoring worksheets, and the original examiner's report — to understand the context and identify any factors that may have contributed to the original outcome. However, the retest scoring should be conducted independently, without being influenced by the original examiner's conclusions.

Matsuda et al. (2006) demonstrated that incorporating pretest data through a latent class discrimination method showed superior discrimination performance compared to conventional approaches [25]Verified A new discrimination method for the concealed information test using pretest data and within-individual comparisons
Demonstrated that latent class discrimination using pretest data showed superior discrimination performance compared to conventional methods. Similarly, Matsuda et al. (2015) found that pretest screening significantly improved diagnostic value, though it led to a substantial number of undiagnosed participants (33.6%), highlighting the trade-off between accuracy and inclusiveness in retesting scenarios [26]Verified Using pretest data to screen low-reactivity individuals in the autonomic-based concealed information test
Found that pretest screening improved diagnostic value but led to 33.6% undiagnosed participants, demonstrating the accuracy-inclusiveness trade-off.

What Research Tells Us About Retesting

Peer-reviewed research provides important insights into how repeated testing affects polygraph accuracy. Dollins, Cestaro, and Pettit (1998) studied the efficacy of repeated psychophysiological detection of deception testing, providing foundational data on how physiological responses change across multiple examinations [27]Verified Efficacy of Repeated Psychophysiological Detection of Deception Testing
Foundational research on the efficacy of repeated polygraph testing relevant to retesting protocols.

Balloun and Holmes (1979) found in a laboratory experiment with a real crime scenario that electrodermal activity (skin resistance) was the only effective physiological measure across examinations, and that cardiovascular channels failed to detect guilt — with detection accuracy vanishing entirely on the second examination [10]Verified Effects of Repeated Examinations on the Ability to Detect Guilt with a Polygraphic Examination: A Laboratory Experiment with a Real Crime
Found that electrodermal activity was the only effective measure across repeated tests; detection accuracy vanished on the second examination. This finding underscores why retesting examiners may benefit from paying particular attention to EDA channels and considering different validated techniques.

At the same time, Lieblich et al. (1974) found that combining GSR (galvanic skin response) data across 10 repetitions of the same items actually reduced detection errors, and surprisingly, motivation level produced no noticeable effect on detection efficiency [11]Verified Efficiency of GSR detection of information with repeated presentation of series of stimuli in two motivational states
Found that combining GSR responses across 10 repetitions reduced detection errors; motivation level had no noticeable effect on detection efficiency. These contrasting findings suggest that the relationship between repetition and accuracy is complex and context-dependent — making it critical that retesting examiners understand the complete guide to how polygraph testing works.

Research by Vrij, Mann, Robbins, and Robinson (2006) on police officers' ability to detect deception in repeated lie detection tests provides further context for how examiner judgment may be affected by familiarity with a case [28]Verified Police officers ability to detect deception in high stakes situations and in repeated lie detection tests
Foundational research on examiner judgment in repeated deception detection contexts. Meanwhile, Izotovas, Vrij, and Strömwall (2021) found that explicit instruction about diagnostic cues showed no improvement in deception detection accuracy, highlighting the importance of relying on validated physiological measurement rather than behavioral observation during retests [29]Verified Mnemonic Techniques and Lie Detection: Accuracy of Truth and Deception Judgments in Repeated Accounts
Found that explicit instruction about diagnostic cues showed no improvement in deception detection accuracy compared to uninformed participants.

Practical Preparation Steps

Preparing for a polygraph retest follows similar principles to preparing for an initial examination, with some additional considerations. The APA recommends that examinees continue normal day-to-day activities, arrive without the distractions of fatigue, hunger, or discomfort, and continue taking prescriptions according to their provider's directions [30]Verified APA FAQ Sheet — Polygraph Preparation Guidelines
Confirms APA guidance on examinee preparation, including continuing normal activities and following medication directions before testing. Avoiding excessive use of stimulants or unnecessary over-the-counter medications before the examination is also advised, as they may cause the session to go significantly longer than normal [30]Verified APA FAQ Sheet — Polygraph Preparation Guidelines
Confirms APA guidance on examinee preparation, including continuing normal activities and following medication directions before testing.

For a retest specifically, you should request copies of the original examination charts and report if available, discuss the original results with your attorney or the retesting examiner, address any medical or psychological factors that may have affected the original results, and allow sufficient time to pass between examinations so that any temporary conditions have resolved.

Testing done in the morning tends to be more productive than those done later in the day, and testing done in the evening significantly increases the risk of an inconclusive result [9]Verified British Polygraph Society FAQ
Confirms recommendation to not test more than 2 times in 12 months and not more than 4 times per year; confirms attorney-client privilege for defense-arranged tests. Establishing a strong, consistent physiological baseline is essential for the examiner's ability to accurately interpret responses to relevant questions.

For couples or individuals dealing with personal matters, our guide on lie detector tests for couples covers preparation specific to relationship-related testing scenarios.