Validity and Reliability of Polygraph Examinations of Criminal Suspects

One of the earliest rigorous field studies of the CQT examining criminal suspects, establishing baseline accuracy data for Department of Justice funded research.

Field study of criminal suspects tested with the CQT. Ground truth established through confessions and judicial outcomes. Physiological recordings analyzed using numerical scoring methods.

Barland and Raskin conducted one of the first methodologically rigorous field studies of the CQT with actual criminal suspects. Funded by the U.S. Department of Justice through the Law Enforcement Assistance Administration, this study established the template for field validation research that would continue for decades. The study demonstrated that field-condition polygraph examinations achieve reliable discrimination between truthful and deceptive subjects, providing crucial evidence that laboratory findings translate to real-world criminal investigation settings. This foundational work was subsequently referenced in every major government review of polygraph science.

As one of the earliest DOJ-funded field validation studies, this research established that polygraph testing works under real investigative conditions with actual criminal suspects facing genuine consequences. The findings laid essential groundwork for the legal and policy acceptance of polygraph evidence.

Background & Context

The Barland and Raskin (1976) study represents a watershed moment in polygraph research, emerging at a critical juncture when law enforcement agencies were increasingly relying on psychophysiological deception detection but lacked rigorous scientific validation. This field study examined the accuracy of the polygraph technique using criminal suspects tested by a private polygraph examiner and referred for examination by defense attorneys or law enforcement agencies. Prior to this work, most polygraph validation had come either from laboratory simulations with limited ecological validity or from field studies with serious methodological flaws.

Funded through contract No. 75-N1-99-0001 by the National Institute of Justice, Department of Justice, this research established the methodological template that would guide field validation studies for decades. The study concluded that, despite limitations, the overall results are consistent with the proposition that carefully administered control question polygraph examinations are highly accurate in assessing the credibility of criminal suspects. This work became one of the most frequently cited studies in every subsequent government review of polygraph science, from the 1983 Office of Technology Assessment report through the 2003 National Research Council review.

Research Design & Methodology

A total of 102 subjects were examined on the polygraph at the request of police, defense attorneys, or prosecuting attorneys in Utah and Nevada. This represented actual criminal suspects facing genuine legal consequences—not volunteers in a laboratory setting. The examinations were conducted by Gordon Barland, who at the time was working as a private polygraph examiner, using the Control Question Test (CQT) format with zone comparison techniques.

Case information provided to the examiner prior to the test sometimes included the initial police report of the incident but was more often limited to that provided by a brief telephone conversation with the defense attorney. Ground truth—the actual guilt or innocence of suspects—was established through a multi-step verification process. One-third of the 92 cases were judged inconclusive by the panel merely on the basis of the investigative files. The figures reported are for 64 of the original 92 cases that could be adequately verified.

The study employed both original examiner decisions and blind chart evaluations. Panelists used in the study each made decisions on all cases in the sample, using a 5-position scale indicating their decision and their confidence in it. Numerical scoring methods were applied to physiological recordings of cardiovascular, electrodermal, and respiratory responses. The effects of various personality and socioeconomic variables that might influence autonomic responsivity in a realistic detection of deception situation were investigated.

Results & Key Findings

The Barland and Raskin study demonstrated that field polygraph examinations could achieve reliable discrimination between truthful and deceptive criminal suspects, though with important caveats about accuracy rates. The original examiner's decisions showed high accuracy for detecting deceptive suspects but revealed concerning error rates for truthful individuals.

Correct guilty detections ranged from 70.6 percent in one condition to 98.6 percent in other field studies, while correct innocent detections were even more variable, ranging from a low of 12.5 percent in the Barland and Raskin judicial outcome study to a high of 94.1 percent. This striking asymmetry—higher accuracy with guilty suspects but substantially lower accuracy with innocent suspects—became a focal point for subsequent debates about polygraph validity.

Key accuracy findings from the verified cases included:

• The study demonstrated significantly better-than-chance discrimination using multiple physiological measures
• Numerical scoring methods showed skin resistance (electrodermal activity) as the most discriminating physiological channel
• Blind chart evaluations by independent scorers achieved moderate to high agreement with ground truth criteria
• Substantial variability in accuracy emerged depending on the type of crime and verification method used

Factors limiting the generalizability of the study were identified as the use of only one polygraph examiner, the inadequacy of the criteria against which the examiner's decisions were compared, and the small number of suspects diagnosed as truthful by the polygraph and innocent by external criteria. This honest acknowledgment of methodological constraints set a standard for scientific integrity in polygraph research.

Discussion & Significance

The Barland and Raskin study's greatest contribution was demonstrating that rigorous field research on polygraph validity was feasible, despite the formidable challenges of establishing ground truth outside laboratory settings. The research showed that with carefully constructed criteria and systematic blind evaluation procedures, field studies could provide meaningful evidence about polygraph accuracy in real-world criminal investigations. This methodology influenced every major field study that followed, from Horvath's work through contemporary validation research.

The study also highlighted a critical asymmetry that would become central to polygraph debates: Many of the investigative files that were given to the panel were incomplete. The files had been compiled by inexperienced student assistants who often did not know where to obtain necessary information. The officials responsible for providing the information were, more often than not, unavailable or unable to recall the details of a crime. This candid acknowledgment of real-world research constraints helped establish more realistic expectations for field validation studies and spurred improvements in methodology for subsequent research.

The findings were incorporated into broader Department of Justice research programs and became foundational evidence in the 1983 Office of Technology Assessment review. Analyses of the Barland and Raskin results by different reviewers yielded varying accuracy estimates depending on how inconclusive decisions and base rates were handled, illustrating the complexity of summarizing polygraph accuracy with single statistics. This study established that polygraph field research required sophisticated statistical treatment and careful consideration of decision thresholds.

Limitations & Considerations

The authors and subsequent reviewers identified several significant limitations that qualify the study's conclusions. Barland and Raskin did not eliminate cases in which investigative files without the polygraph were inadequate. Many of the investigative files were incomplete, with few details available in many cases. As a result, one-third of the 92 cases were judged inconclusive by the panel merely on the basis of the investigative files.

Additional methodological concerns included:

• Use of a single examiner limits generalizability across examiners with varying skill levels
• Ground truth criteria based on confessions and judicial outcomes may be contaminated by the polygraph results themselves
• The sample included very few cases where suspects were diagnosed as truthful by the polygraph and verified as innocent by external criteria
• Selection of cases from defense attorney referrals may have introduced systematic bias in the sample composition
• Quality control reviews do not fully control for the impact of interpersonal expectancy effects, which would still be reflected in the original polygraph charts

Practical Applications

This research provided crucial evidence that polygraph testing could function effectively in authentic criminal investigations, not just controlled laboratory settings. The study validated numerical scoring approaches and multi-channel physiological recording as essential components of rigorous polygraph practice. Law enforcement agencies and courts increasingly cited this work as evidence supporting the admission and use of polygraph results, though the documented limitations also provided ammunition for polygraph critics.

For contemporary polygraph practice, the Barland and Raskin study underscores the critical importance of proper case documentation, independent verification of ground truth, and acknowledgment of accuracy limitations—particularly the asymmetric error rates that tend to disadvantage truthful examinees. The research demonstrated that single-examiner studies, while valuable, must be supplemented with multi-examiner research to establish technique generalizability. Modern examiners should recognize that the methodological challenges identified in this pioneering work—incomplete case files, verification difficulties, and potential examiner bias—remain relevant concerns in current practice.