False Positive (PDD)
Definition
A truthful person classified as deceptive by the polygraph examination. The rate of false positives in field conditions is non-trivially high and is a primary basis for exclusionary court rules.
- Field
- Polygraph deception detection (PDD)
- Outcome
- Truthful subject classified as deceptive
- Legal relevance
- Cited basis for exclusionary rules such as US v. Scheffer
- Contrast
- Distinct from false negative, a deceptive subject scored truthful
Common questions
Why do false positives occur more often than false negatives in polygraph testing?+
Anxious but truthful subjects can produce physiological arousal similar to a deceptive response, while a calm, trained, or countermeasure-using deceptive subject can suppress the reactions the test relies on, which skews field error patterns toward wrongly flagging honest people.
How does the false positive rate affect polygraph admissibility?+
Courts weighing admissibility, including the US Supreme Court in Scheffer, have pointed to the lack of a single agreed error rate and the risk of an honest examinee being branded deceptive as reasons to exclude or restrict polygraph results as evidence of guilt.
Related terms
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- BSA § 39
- Section 39 of the Bharatiya Sakshya Adhiniyam 2023 (formerly IEA § 45), governing the admissibility of expert opinion in Indian courts. The...
- Concealed Information Test (CIT)
- The Lykken paradigm that detects concealed knowledge by measuring the orienting response to crime-specific items embedded among foils. Theoretically sounder than the...
- Control Question Test (CQT)
- The dominant polygraph examination format, comparing physiological responses to crime-relevant questions against responses to emotionally loaded control questions. Criticised for its false-positive...
- Frye Standard
- The US legal test for admissibility of scientific evidence, originating from Frye v. United States (1923), which required that a technique be...
- NRC 2003
- The National Research Council's *The Polygraph and Lie Detection* (2003), the most comprehensive scientific review of polygraph validity. Found no scientific basis...
- Polygraph (PDD)
- A multichannel physiological recording instrument capturing electrodermal activity, cardiovascular parameters, and respiration. The term is used interchangeably with the examination technique; the...
- Selvi V. State of Karnataka (2010)
- Constitutional bench judgment (2010) 7 SCC 263 holding that compelled narco-analysis, polygraph testing, and brain-mapping violate Article 20(3) and Article 21 of...
- US V. Scheffer (1998)
- US Supreme Court decision upholding the per se exclusion of polygraph evidence in military courts under Military Rule of Evidence 707, on...