A Field Study of the Validity of the Directed Lie Control Question

First field validation of the directed-lie comparison question format, demonstrating its accuracy equals or exceeds the traditional probable-lie CQT.

Field study comparing directed-lie control question (DLC) format against probable-lie CQT in actual criminal investigations.

Honts and Raskin conducted the first field validation of the directed-lie comparison question format, a significant procedural innovation. Results demonstrated that the DLC format was at least as accurate as the traditional probable-lie CQT while producing fewer false positive errors. The directed-lie format offers practical advantages: comparison questions are simpler to construct, require less pre-test interview skill, and produce more standardized baseline responses. This study established the DLC as a validated alternative that would be widely adopted across the profession.

The DLC validation represented a major practical advance, giving examiners a validated format that is easier to administer, more standardized, and produces fewer false positives. The subsequent widespread adoption of directed-lie formats across federal and private practice has improved overall testing quality.

Background & Context

The Honts and Raskin (1988) study represents a watershed moment in polygraph science, marking the first field validation of the directed-lie comparison question (DLCQ) format. Prior to this research, the probable-lie comparison question technique, introduced by John Reid in 1947, dominated polygraph practice. However, probable-lie questions required substantial interviewing skill and psychological sophistication to construct effectively—a challenge for many examiners in the field.

The directed-lie approach offered a practical solution: it was positioned as a valid and valuable tool in physiological detection of deception while reducing inconclusive outcomes and false positive errors. This study emerged from a larger National Institute of Justice-funded research program examining polygraph validity in criminal investigations, positioning it within the most rigorous field research efforts of the era.

The research addressed a critical gap between laboratory findings and field application. While the directed-lie concept had theoretical promise, no field study had yet validated whether it would perform comparably to the established probable-lie method when used with actual criminal suspects in real-world investigative contexts.

Research Design & Methodology

The study examined 25 criminal suspects referred to the authors for polygraph examinations between January 1983 and January 1987, with 13 examinations later confirmed as innocent subjects and 12 confirmed as guilty subjects. This within-subjects design was particularly powerful: each examinee received both directed-lie and probable-lie comparison questions in the same examination, allowing direct comparison of the two formats.

Physiological recordings used laboratory or field polygraphs and measured respiration, relative blood pressure, electrodermal activity, and peripheral vasomotor activity, with subjects receiving a stimulation test followed by three to five presentations of question sequences in varying orders. The ground truth—confirmation of actual guilt or innocence—came from independent verification through confessions, corroborating evidence, or resolution of the criminal cases.

Key design elements included:

• Within-subjects comparison of directed-lie vs. probable-lie comparison questions
• Confirmed outcomes through case resolution (essential for field study validity)
• Standard Utah CQT protocol with multiple physiological channels
• Counterbalanced question order across chart presentations
• Real criminal suspects with genuine consequences

Results & Key Findings

The findings demonstrated that the DLCQ is a valid tool, with replacement of one comparison question with a directed-lie question reducing inconclusive outcomes and false positives while increasing the strength of the relationship between decisions and the guilt/innocence criterion. This was the critical validation the field needed: directed-lie questions performed at least as well as probable-lie questions, and in some measures performed better.

The study's most significant contributions included:

• Reduced false positive errors—fewer innocent people incorrectly classified as deceptive with the DLC format
• Fewer inconclusive outcomes—more definitive results allowing clearer investigative decisions
• Stronger criterion relationship—improved correlation between test outcomes and actual guilt/innocence
• Equivalent overall accuracy—no sacrifice in detection capability compared to the established probable-lie method

Later reanalysis of these same 25 confirmed field cases examined directed-lie and probable-lie comparison questions contrasted within subjects, with subsequent research consistently showing that numerical scores differ significantly for guilty and innocent examinees using both formats. The practical advantage was clear: examiners could achieve comparable or superior results with a more standardized, easier-to-administer question format.

Discussion & Significance

This study fundamentally altered polygraph practice by providing empirical validation for a procedural innovation that simplified test administration while maintaining or improving accuracy. The directed-lie format addressed longstanding criticisms about the subjective nature of comparison question construction in probable-lie testing, offering a more standardized baseline that reduced examiner variability.

The theoretical significance was equally important. The increased strength of the relationship between decisions and the guilt/innocence criterion suggested that directed lies might produce more consistent physiological activation in innocent examinees—a key requirement for effective comparison questions. The reduction in false positives was particularly meaningful for protecting innocent suspects from wrongful conclusions.

The study's impact on the field was immediate and lasting. Within years of publication, federal agencies, including the Department of Defense, began transitioning to directed-lie formats for both specific-issue testing and security screening applications. The research contributed to the broader University of Utah program that established much of the empirical foundation for modern polygraph testing, as documented in their comprehensive NIJ-funded validation studies.

Limitations & Considerations

The study's primary limitation was its modest sample size of 25 confirmed cases accumulated over four years. While adequate for establishing preliminary validity, this represented the challenge inherent in field research: obtaining confirmed ground truth cases with sufficient numbers for robust statistical analysis is difficult and time-consuming. The long collection period (1983-1987) also meant examinations occurred under varying circumstances across different investigations.

Additional considerations include:

• The study occurred in a single laboratory with experienced examiners, limiting generalizability to less skilled practitioners
• Case confirmation methods varied depending on investigation outcomes
• The within-subjects design, while scientifically strong, meant examiners couldn't be blind to comparison question type
• No analysis of differential effects across crime types or suspect populations

The research also couldn't address whether the observed advantages would hold across different scoring systems or with less experienced examiners—questions that subsequent research would need to explore.

Practical Applications

This research provided examiners with a validated alternative that offers significant practical advantages. Directed-lie comparison questions are straightforward to construct and don't require the psychological sophistication needed to develop effective probable-lie questions. For examinations like "Before age 25, did you ever lie to someone in authority?"—the examinee is simply instructed to answer "no" when the truthful answer is obviously "yes." This standardization reduces training requirements and improves consistency across examiners.

For consumers and attorneys evaluating polygraph evidence, the study supports the validity of examinations using directed-lie formats—which are now standard in many federal agencies and private practices. The demonstrated reduction in false positives is particularly important for protecting the innocent. However, test quality still depends fundamentally on examiner competence, proper test construction, appropriate question formulation, and adherence to standardized protocols. The directed-lie format is a validated tool, but like any scientific instrument, its accuracy depends on skilled and ethical application.