Polygraph Glossary Scoring

Cut-Score

Also known as — Decision Threshold

Definition

The numerical boundary in a scoring system that separates deceptive from non-deceptive classifications. Scores above the positive cut-score indicate truthfulness (NDI); scores below the negative cut-score indicate deception (DI); scores between the two are classified as inconclusive. Cut-scores are empirically derived from validated research samples and directly affect the balance of sensitivity, specificity, and inconclusive rates.

What Is Cut-Score?

Cut-Score (Decision Threshold) is a polygraph scoring concept. The numerical boundary in a scoring system that separates deceptive from non-deceptive classifications. Scores above the positive cut-score indicate truthfulness (NDI); scores below the negative cut-score indicate deception (DI); scores between the two are classified as inconclusive. Cut-scores are empirically derived from validated research samples and directly affect the balance of sensitivity, specificity, and inconclusive rates.

Role of Cut-Score in Polygraph Scoring

Scoring methodology is one of the most critical factors affecting polygraph accuracy. The evolution from subjective global evaluation to structured numerical scoring and automated algorithms has significantly improved the reliability and reproducibility of polygraph results, as measured by interrater reliability studies.

Modern scoring approaches analyse physiological responses across multiple channels — electrodermal activity (considered the most diagnostically powerful single channel), respiratory patterns, and cardiovascular changes — using validated Kircher features that have demonstrated replicable diagnostic value across decades of research.

Practical Application

APA Standards of Practice require the use of validated scoring methods for all diagnostic and screening polygraph examinations. The choice of scoring system directly affects the cut-scores applied for classification decisions (Deception Indicated, No Deception Indicated, or Inconclusive) and the overall balance between false positives and false negatives.

Related Terms

Understanding Cut-Score in context requires familiarity with several related polygraph concepts:

Key Takeaways

Cut-Score is an important concept within the field of Psychophysiological Detection of Deception. Whether you are a polygraph examiner, student at an APA-accredited training program, legal professional evaluating polygraph evidence, or a private individual preparing for a lie detector test, understanding this term and its relationship to other polygraph concepts will help you navigate the field with greater confidence and knowledge.

The science of polygraph testing has evolved significantly over more than 100 years, from the early work of William Moulton Marston and Leonarde Keeler to today's digital instruments and validated scoring algorithms. Every term in this glossary represents a piece of that scientific and professional heritage. For a comprehensive overview, visit the Polygraph Examiner Hub or use our examiner selection guide to find a professional examiner near you.

Cross-references

More scoring terms in this glossary

relief tracing A relief tracing is the section of a physiological recording where recovery from arousal is apparent — the return tow... CPSComputerized Polygraph System A computerised scoring system developed by Scientific Assessment Technologies based on University of Utah research. A... spot analysis Spot analysis is the numerical evaluation of a Relevant Question by comparing it to an adjacent Comparison Question. ... Variance A statistical measure of the spread or dispersion of physiological response scores within a polygraph data set. Analy... chi-square test The chi-square test (χ²) is a non-parametric inferential statistical test used to evaluate relationships between cate... true negative A true negative is a correct PDD decision that the examinee is not deceptive — an accurate outcome of truthfulness. S...

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