Polygraph Test Cost vs. Value: Is It Worth the Investment?

National Pricing Overview

Across the United States, private polygraph examinations generally fall within a range of $200 to $2,000 or more. For the most commonly requested tests — such as infidelity or personal issue polygraphs — expect to pay between $300 and $600. More complex examinations, such as those used in criminal defense or involving multiple issues, can reach $800 to $2,000+.

According to Wired magazine (2018), an estimated 2.5 million polygraph tests are administered each year in the United States, with the majority given to paramedics, police officers, firefighters, and state troopers [1]Verified Polygraph — Wikipedia
Confirms 2.5 million polygraph tests annually in the U.S. per Wired (2018), annual federal polygraph testing figures, and U.S. v. Scheffer jurisdictional admissibility ruling. The average cost to administer a test in professional settings exceeds $700 [1]Verified Polygraph — Wikipedia
Confirms 2.5 million polygraph tests annually in the U.S. per Wired (2018), annual federal polygraph testing figures, and U.S. v. Scheffer jurisdictional admissibility ruling.

Here is a general breakdown of current market pricing:

Single-issue personal/relationship test: $300 - $600 Multi-issue personal test: $400 - $800 Pre-employment screening (per candidate): $200 - $500 Criminal defense / attorney-ordered: $800 - $2,000+ PCSOT (sex offender supervision): $300 - $600 Federal law enforcement screening (agency-administered): No cost to candidate

These prices typically include the pre-test interview, chart collection (the actual polygraph examination), and a post-test interview. However, written reports, additional question sets, and travel fees may or may not be included, so always clarify the full scope before committing. For current rates specific to your situation, you can find a private lie detector test near you.

What Is Included in a Standard Polygraph Fee

When you pay for a professional polygraph examination, the cost covers far more than simply sitting in a chair with sensors attached. A properly conducted examination typically involves three distinct phases, each requiring the examiner's expertise, time, and professional equipment.

The pre-test interview generally lasts 45 minutes to over an hour. During this phase, the examiner reviews your case background, explains the instrument and procedure, discusses the specific test questions, and ensures you are physically and psychologically suitable for testing. Understanding how examinees with conditions like borderline personality disorder respond can influence the examiner's approach.

The chart collection phase — the actual polygraph test — lasts approximately 15 to 30 minutes, during which the examiner asks the agreed-upon questions multiple times while monitoring your physiological responses. Most examiners collect at least three charts to ensure consistency and reliability. The deceptive reaction zone is the portion of the chart where meaningful physiological responses are evaluated.

The post-test interview involves reviewing the results, discussing any significant reactions, and — depending on the examiner and situation — providing preliminary findings. Some examiners also provide a written report, which may sometimes carry an additional fee.

Your fee also implicitly covers the examiner's professional training (typically a minimum of 250+ classroom hours at an APA-accredited program), ongoing continuing education, professional liability insurance, equipment maintenance, and office overhead. Professional-grade polygraph instruments from manufacturers like Lafayette Instrument Company — including their latest LX6 and LX7 systems — represent a significant investment for examiners [2]Verified Lafayette Instrument Company — LX6 Polygraph System
Confirms Lafayette as world's leading manufacturer of polygraph instrumentation with modern computerized multi-channel systems. The polygraph system lifespan and proper maintenance directly affect test quality.

Why Prices Vary So Much

If you've been shopping around for polygraph services, you've probably noticed a wide spread in pricing. A $250 examiner in one city might seem like a bargain next to an $800 examiner in another. But price alone tells you very little about quality. Be wary of polygraph pricing that seems too good to be true.

Geographic Location: Cost of living directly impacts pricing. Examiners in major metropolitan areas like New York City, Los Angeles, or Washington D.C. typically charge more than those in smaller markets. A test in Manhattan might cost $700+ while the same examination in a rural Midwest area might be $300.

Examiner Qualifications and Experience: An examiner with 20+ years of experience, APA membership, advanced certifications, and a track record in court testimony will command higher fees. This premium reflects genuine expertise that produces more reliable results.

Type of Examination: A straightforward single-issue specific test is less expensive than multi-faceted criminal defense examinations that may require extensive file review, coordination with attorneys, and potential expert testimony. The APA's meta-analysis found that single-issue diagnostic testing produces an aggregated decision accuracy of 89% (CI: 83-95%), while multi-issue tests achieve 85% (CI: 77-93%) [3]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms APA meta-analysis found 87% overall accuracy (CI: 80-94%), 89% for single-issue tests (CI: 83-95%), and 85% for multi-issue tests (CI: 77-93%).

Travel Requirements: If the examiner must travel to your location, expect travel fees. Be cautious of examiners who advertise home-based polygraph testing as standard practice, as proper testing requires controlled environments.

Written Report and Expert Testimony: Some fees include a basic verbal summary, while a comprehensive written report suitable for attorneys, courts, or employers may cost an additional $100-$300. Expert testimony in court can cost $500-$2,000+ per appearance. Always verify reports are genuine — fake polygraph results are a real concern.

Urgency and Scheduling: Need an exam within 24-48 hours? Rush scheduling often carries a premium. Standard scheduling with 1-2 weeks lead time typically avoids these surcharges.

Thinking Beyond the Price Tag

The true question isn't "how much does a polygraph cost?" — it's "what is the cost of NOT getting one?" In virtually every scenario where someone considers a polygraph, there's an existing problem that is already costing them money, emotional health, relationships, or freedom. The polygraph fee must be weighed against these ongoing and potential costs.

Think of it like medical diagnostics. An MRI might cost $1,000+, but nobody questions the value when it determines whether you need surgery or simply physical therapy. A polygraph serves a similar diagnostic function for truth — it provides data that helps you make better decisions about your life, your relationships, or your legal strategy. Research on the value of psychophysiological stimuli demonstrates that there is a formalized relationship between stimulus psychological significance and physiological response magnitude, supporting the polygraph's diagnostic utility [4]Verified Probability Assessment of the Value of Psychophysiological Stimuli
Foundational research on the relationship between stimulus psychological significance and physiological response magnitude in polygraph testing.

The Cost of Suspicion vs. The Cost of Certainty

Relationship and infidelity polygraph testing is one of the most commonly requested private polygraph services. Individuals facing trust crises in their marriages or partnerships often spend months — even years — trapped in a painful cycle of suspicion, accusation, denial, and emotional deterioration.

Consider the real-world costs of unresolved infidelity suspicion:

Couples therapy: At $150-$300 per session, weekly therapy for six months costs $3,600-$7,200 — and many couples attend far longer when trust remains unresolved.

Individual therapy: The betrayed partner often needs their own therapy at similar rates, adding another $2,000-$5,000 or more.

Unnecessary divorce: According to Forbes, the average cost of a divorce in 2024 ranges from $7,000 to $15,000, with the average cost with attorneys reaching $11,300 [5]Verified Average Cost of Divorce in the U.S.
Confirms average divorce cost ranges from $7,000 to $15,000 according to Forbes data for 2024. Contested divorces involving custody disputes can easily exceed $50,000 [6]Verified How Much Does a Divorce Cost? The Complete Breakdown
Confirms average cost of divorce with attorneys is $11,300 with a median of $7,000.

Children's wellbeing: The impact on children of parents in constant conflict is immeasurable but profoundly real.

Against these costs, a $300-$600 infidelity polygraph is remarkably affordable. If your partner is telling the truth, the test provides powerful reassurance that can shortcut months of therapy and rebuild trust rapidly. If deception is indicated, you gain the clarity needed to make informed decisions about your future. For individuals noticing warning signs, our guides on signs your wife might be cheating or signs your husband might be cheating can help assess the situation.

Real-World Value Calculation: Infidelity Scenario

Consider a concrete example. Sarah suspects her husband James of having an affair. She's been in individual therapy for three months ($1,800 so far), they've attended eight couples therapy sessions ($2,000), and she's spending hours each day monitoring his phone and social media instead of being productive at work.

Her attorney has quoted $15,000-$20,000 for a contested divorce. A polygraph examination costs $450.

If James passes, Sarah has objective data to support the therapeutic process and begin genuinely healing. If James fails, Sarah can proceed with confidence to make whatever decisions she needs — whether that's demanding full disclosure and intensive therapy, or moving forward with separation.

Either way, the $450 provides resolution that thousands of dollars in therapy and legal consultation have not. That's not just a good investment — it's one of the most cost-effective decisions available in that situation. Research confirms that first impressions of trustworthiness are unreliable — intuitive judgments of whether someone is being honest operate near chance levels [7]Verified Is the Face a Window to the Soul? Investigation of the Accuracy of Intuitive Judgments of the Trustworthiness of Human Faces
Confirms intuitive trustworthiness judgments of criminal faces were at chance level (M = 48.8%), supporting the value of objective deception detection tools — which is precisely why objective tools like the polygraph provide such value.

When Your Liberty Is at Stake

In criminal defense situations, the value of a polygraph extends far beyond money — it can directly influence whether someone faces years of incarceration or walks free. Criminal defense attorneys increasingly use polygraph examinations as strategic tools.

A criminal defense polygraph typically costs between $800 and $2,000+, which may seem substantial until you consider the alternatives. Criminal defense attorney fees alone commonly range from $5,000 to $50,000+ depending on the severity of the charges and complexity of the case.

A single felony conviction can result in:

Direct legal costs: $10,000-$100,000+ in attorney fees, fines, and court costs.

Lost income during incarceration: $30,000-$60,000+ per year of imprisonment.

Lifetime earnings reduction: According to the Brennan Center for Justice, a felony conviction reduces annual earnings by approximately 22%, while imprisonment reduces earnings by roughly 52% compared to peers [8]Verified Conviction, Imprisonment, and Lost Earnings: How Involvement with the Criminal Justice System Deepens Inequality
Confirms felony conviction reduces annual earnings by approximately 22%, imprisonment reduces earnings by approximately 52%, and lifetime earnings loss averages $484,400 for formerly imprisoned individuals. Over a lifetime, someone imprisoned as a young adult suffers an average of approximately $484,400 in lost earnings [8]Verified Conviction, Imprisonment, and Lost Earnings: How Involvement with the Criminal Justice System Deepens Inequality
Confirms felony conviction reduces annual earnings by approximately 22%, imprisonment reduces earnings by approximately 52%, and lifetime earnings loss averages $484,400 for formerly imprisoned individuals.

Loss of professional licenses: Many careers — healthcare, law, finance, education — are closed to those with felony convictions. Research indicates that approximately 27,000 rules nationwide bar people with criminal records from obtaining professional licenses [8]Verified Conviction, Imprisonment, and Lost Earnings: How Involvement with the Criminal Justice System Deepens Inequality
Confirms felony conviction reduces annual earnings by approximately 22%, imprisonment reduces earnings by approximately 52%, and lifetime earnings loss averages $484,400 for formerly imprisoned individuals.

Collateral consequences: Housing restrictions, potential loss of voting rights in some states, custody complications, and social stigma.

An $800-$2,000 polygraph that helps negotiate a favorable plea bargain, influences a prosecutor to reduce or drop charges, or strengthens a defense strategy is an extraordinarily efficient investment. Understanding the differences between private and court-ordered polygraphs is essential for anyone navigating the legal system.

How Defense Attorneys Use Polygraph Results

Understanding how polygraph evidence is used in legal proceedings reveals several pathways where the investment generates returns:

Pre-indictment negotiations: A passed polygraph presented to prosecutors before charges are formally filed can sometimes prevent charges entirely.

Plea bargain leverage: Polygraph results can strengthen a defendant's negotiating position, potentially resulting in reduced charges or more favorable sentencing recommendations.

Probation and parole considerations: Courts may view a passed polygraph favorably when making decisions about supervised release.

Civil litigation support: In cases involving civil litigation, polygraph results can influence settlement negotiations.

Internal defense strategy: Even if results aren't shared externally, they help the defense team assess the credibility of their own client and build the most effective strategy.

Research shows that untrustworthy-looking defendants are convicted based on less evidence and with greater confidence than trustworthy-looking defendants [9]Verified Dangerous decisions: The impact of first impressions of trustworthiness on the evaluation of legal evidence and defendant culpability
Confirms untrustworthy-looking defendants were convicted based on less evidence, supporting the need for objective credibility assessment tools. This finding underscores why objective credibility assessment tools like the polygraph can be especially valuable — they provide evidence-based data that transcends subjective biases.

The key consideration is that the polygraph must be conducted by a highly qualified examiner using validated testing protocols. In legal contexts, cutting corners on a legal defense polygraph can be worse than not getting one at all. Examiners should use APA-validated techniques, which require at least 90% accuracy for specific-issue testing [3]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms APA meta-analysis found 87% overall accuracy (CI: 80-94%), 89% for single-issue tests (CI: 83-95%), and 85% for multi-issue tests (CI: 77-93%).

The Business Case for Pre-Employment Screening

For business owners and HR directors, pre-employment polygraph testing represents a cost-effective risk mitigation tool in authorized contexts. While the Employee Polygraph Protection Act (EPPA) of 1988 restricts most private employers from using polygraphs, there are important exemptions — including security services, pharmaceutical companies, and government contractors — where screening is both legal and standard practice [10]Verified Employee Polygraph Protection Act
Confirms EPPA restricts most private employers from using polygraphs but provides exemptions for security services, pharmaceutical companies, and government contractors.

The economics of pre-employment screening are compelling:

Cost per screening: $200-$500

Average employee theft loss: According to the 2021 National Retail Security Survey, the average loss per employee theft incident for retailers exceeded $1,500, compared to just $460 per shoplifting incident [11]Verified 13 Employee Theft Statistics You Should Know
Confirms NRF 2021 National Retail Security Survey found average loss per employee theft incident for retailers exceeds $1,500. More recent NRF data indicates the average loss per internal theft investigation reached $2,180 in 2022 [12]Verified Organized Retail Crime and Theft — NRF 2023 National Retail Security Survey
Confirms average dollar loss for internal theft was $2,180 per investigation in 2022 and retail shrink reached $112.1 billion.

Cost of a bad hire: The U.S. Department of Labor estimates that a bad hire can cost up to 30% of the employee's first-year earnings [13]Verified The True Cost of Bad Hires
Confirms U.S. Department of Labor estimate that a bad hire can cost up to 30% of employee's first-year earnings.

Hiring replacement cost: According to SHRM's latest benchmarks, the average cost per hire is approximately $4,700, a 14% increase from the 2019 figure of $4,129 [14]Verified SHRM Benchmarking Report: Average Cost-per-Hire
Confirms SHRM cost per hire rose from $4,129 (2019) to $4,700 (2023), a 14% increase.

Employee theft costs U.S. businesses an estimated $50 billion annually [15]Verified Employee Theft Statistics for 2025
Confirms employees steal an average of $1,890 from retailers and that employee theft costs businesses $50 billion annually, and employee theft is a factor in approximately 30% of corporate bankruptcies [15]Verified Employee Theft Statistics for 2025
Confirms employees steal an average of $1,890 from retailers and that employee theft costs businesses $50 billion annually. When a $350 screening prevents even one theft incident, embezzlement scheme, or negligent hiring claim, the return on investment is measured in multiples, not percentages.

For employers dealing with existing theft or workplace integrity issues, our guide on how to book a theft investigation polygraph covers the process, while domestic theft polygraph testing addresses situations involving household members.

Law Enforcement Pre-Employment Value

For individuals pursuing careers in law enforcement, the polygraph is typically administered and paid for by the hiring agency — meaning there's no direct cost to the candidate. As of 2013, approximately 70,000 job applicants are polygraphed by the federal government annually [1]Verified Polygraph — Wikipedia
Confirms 2.5 million polygraph tests annually in the U.S. per Wired (2018), annual federal polygraph testing figures, and U.S. v. Scheffer jurisdictional admissibility ruling. The DOJ reported that major agencies including the FBI, DEA, and ATF conducted an average of more than 12,000 tests each year [16]Verified The Effectiveness and Future of Polygraph Testing
Confirms approximately 2.5 million polygraph tests conducted in the U.S. each year and DOJ reporting of 12,000+ annual tests across major federal agencies.

From the agency's perspective, the pre-employment polygraph for a single officer position that costs $300-$500 to administer protects against potentially millions of dollars in liability. The case of Ana Montes and the DIA polygraph illustrates both the value and limitations of screening programs — and why continuous improvement in testing methodology matters.

Federal agencies like the FBI, CIA, and NSA invest heavily in national security polygraph screening precisely because the cost-benefit ratio is overwhelmingly favorable, despite the National Academy of Sciences' 2003 finding that screening accuracy is lower than specific-incident testing [17]Verified The Polygraph and Lie Detection
Confirms NAS 2003 report found specific-incident polygraph tests discriminate lying from truth at rates well above chance, though well below perfection; median accuracy estimated at.85.

The Incalculable Value of Clearing Your Name

Being falsely accused of a crime, sexual misconduct, theft, or other wrongdoing is one of the most devastating experiences a person can face. The accused often loses their job, their reputation, their relationships, and their mental health — sometimes before any formal investigation concludes.

Consider what's at stake:

Career destruction: Many employers terminate accused individuals before adjudication, and the stigma of an accusation can follow someone for years.

Relationship damage: Friends, family, and romantic partners may distance themselves based on the accusation alone.

Mental health crisis: False accusations commonly trigger severe anxiety, depression, PTSD symptoms, and suicidal ideation.

Legal fees: Defending against false accusations can easily cost $10,000-$50,000+ even when charges are ultimately dropped.

A polygraph examination costing $400-$800 that provides supporting evidence of truthfulness can accelerate investigations, influence prosecutorial decisions, and provide powerful documentation. Research on deception detection confirms that lies involving high emotional stakes produce significantly larger physiological cues — with effect sizes for nervousness (d=0.35) and voice pitch (d=0.59) substantially higher in high-motivation conditions [18]Verified Lies worth catching involve both emotion and cognition
Confirms high-motivation deception produces larger physiological cues (nervousness d=0.35, voice pitch d=0.59) supporting polygraph effectiveness in high-stakes testing — making high-stakes polygraph examinations particularly effective.

While a polygraph alone may not conclusively resolve an accusation, it adds a significant data point that — when combined with other evidence — can substantially influence outcomes. Understanding how polygraph countermeasures are detected also helps reinforce the integrity of a passed examination.

Therapeutic Polygraph: Accelerating Truth and Healing

Mental health professionals increasingly incorporate polygraph examinations into treatment protocols, particularly in cases involving addiction, trust violations, and relationship repair. The sexual addiction disclosure polygraph is a prime example of how a single examination can compress months of therapeutic progress into a single session.

In traditional therapy, disclosure of problematic behaviors often occurs in slow, incomplete increments — sometimes referred to as "staggered disclosure" — with each new revelation re-traumatizing the betrayed partner. A structured disclosure polygraph, typically costing $400-$600, creates accountability that encourages full disclosure in a therapeutic setting.

Therapists who use polygraph-supported therapy report that clients progress through the trust-rebuilding phase significantly faster than those relying solely on verbal disclosure. When you consider that the average couple in post-infidelity therapy attends sessions for 12-24 months at $150-$300 per session, a single polygraph that accelerates progress by even a few months represents significant financial and emotional savings.

PCSOT: Community Safety and Rehabilitation Value

Post-Conviction Sex Offender Testing (PCSOT) represents a specialized category where the value extends beyond the individual to the entire community. PCSOT is common in the United States and increasingly applied in England and Wales [19]Verified Post-conviction polygraph testing of sex offenders
Confirms PCSOT is commonly used in the US and increasingly in England and Wales for sex offender supervision.

Research consistently demonstrates that polygraph-monitored sex offenders disclose significantly more risk-relevant information than those supervised without polygraph. A 2018 systematic review by Elliott and Vollm examined 19 studies from the US, UK, and Netherlands, all of which established that PCSOT elicits a significant increase in disclosures relevant to the supervision of those who have committed sexual offenses [20]Verified Why polygraph testing does not consistently lead to reduced recidivism for individuals convicted of sexual offending
Confirms systematic review of 19 studies found PCSOT consistently elicits significant increase in risk-relevant disclosures. A 2020 PLOS One study confirmed that participants in the polygraph group disclosed more deviant sexual behaviors and paraphilia interests compared to the comparison group [21]Verified Improving the quality of sexual history disclosure on sex offenders: Emphasis on a polygraph examination
Confirms polygraph group disclosed more deviant sexual behaviors and paraphilia interests, supporting PCSOT effectiveness as a disclosure tool.

The Colorado Department of Public Safety's landmark study provided critical empirical evidence about PCSOT implementation and effectiveness during a period when this supervision tool was becoming increasingly prevalent [22]Verified The Value of Polygraph Testing in Sex Offender Management
Provided critical empirical evidence about PCSOT implementation and effectiveness during the formative period of this supervision approach. While polygraph use in sex offender management serves primarily as a management and treatment tool rather than as legal evidence, its utility in encouraging disclosure and supporting risk assessment is well-documented [20]Verified Why polygraph testing does not consistently lead to reduced recidivism for individuals convicted of sexual offending
Confirms systematic review of 19 studies found PCSOT consistently elicits significant increase in risk-relevant disclosures.

Content-based deception detection methods, used alongside polygraph, show that accuracy rates can vary based on calculation methods and scoring approaches — reinforcing the importance of using validated, standardized protocols [23]Verified Value of Content-Based Deception Detection Methods
Confirms accuracy rates vary significantly based on calculation methods and scoring approaches in deception detection research.

Counting the Cost of Inaction

Many people focus exclusively on what a polygraph costs, without ever calculating the cost of not getting one. Consider these scenarios:

The couple who spends $15,000 on therapy over two years because they couldn't establish a baseline of truth that a $450 polygraph could have provided in an afternoon.

The falsely accused employee who loses a $75,000 salary position and spends $30,000 on legal defense when a $600 polygraph examination could have been presented early in the process.

The business owner who suffers $200,000 in employee theft losses over three years because the cost of $350 pre-employment screening seemed like an unnecessary expense.

The criminal defendant who accepts a plea deal for a crime they didn't commit because their attorney didn't consider the strategic value of a $1,200 defense polygraph.

In each case, the cost of the polygraph is a rounding error compared to the cost of the problem it could have addressed. Whether the issue is trust, truthfulness, or security, early intervention with a quality polygraph examination almost always costs less than the alternative path.

Red Flags in Bargain Polygraph Services

The difference between a competent polygraph examination and a cheap one can be the difference between reliable data and a wasted fee — or worse, a harmful false result.

Warning signs of substandard polygraph services include:

Examiners not trained at APA-accredited schools or without APA membership.

Use of outdated, non-computerized equipment. Modern instruments from manufacturers like Lafayette Instrument Company offer sophisticated multi-channel systems with computerized scoring algorithms [2]Verified Lafayette Instrument Company — LX6 Polygraph System
Confirms Lafayette as world's leading manufacturer of polygraph instrumentation with modern computerized multi-channel systems — examiners using older analog equipment may produce less reliable results.

Compressed timelines suggesting corners are being cut (a proper exam takes 1.5-3 hours minimum).

No pre-test interview or abbreviated pre-test (this phase is essential for valid results).

Examiners who guarantee specific outcomes before the test.

Lack of professional liability insurance.

No willingness to provide a written report or testify about findings.

A quality examiner using validated techniques represents a dramatically better investment, even at a higher price point. The APA's meta-analysis confirmed that validated techniques meeting their Standards of Practice produce decision accuracy of 87% overall, with single-issue tests reaching 89% [3]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms APA meta-analysis found 87% overall accuracy (CI: 80-94%), 89% for single-issue tests (CI: 83-95%), and 85% for multi-issue tests (CI: 77-93%). These results depend entirely on proper protocol adherence and examiner competence. The history of polygraph testing shows how technique and standards have evolved significantly over decades.

Emerging alternatives like fMRI lie detection remain largely experimental and prohibitively expensive compared to established polygraph methods.

A Framework for Your Decision

To determine whether a polygraph is worth the investment in your specific situation, consider this framework:

1. What is the problem costing you right now? Add up therapy costs, legal fees, lost productivity, emotional toll on your health and relationships, and any other tangible or intangible costs.

2. What will it cost if the problem continues unresolved? Project these costs forward 6-12 months. In most cases, unresolved truth disputes escalate in cost over time.

3. What is the cost of the polygraph? Get quotes from qualified examiners, always ensuring they meet APA standards.

4. What are the possible outcomes and their value? A "passed" result typically provides clarity and saves ongoing costs. A "deception indicated" result, while sometimes unwelcome, provides equally valuable data for making informed decisions.

5. Calculate the differential. In virtually every scenario, the polygraph fee is a small fraction of the ongoing cost of the problem. The question then becomes not "can I afford a polygraph?" but "can I afford not to get one?"

For a comprehensive understanding of what a lie detector test actually involves, our complete guide walks through every step of the process.