Statement Analysis - Criticism

Criticism

Aldert Vrij, one of the leading authorities on detection of deception (DOD) techniques, points out that most studies of the technique did not rely on the ground truth being established and thus examiners could not be certain if "examinees were actually telling the truth or lying." He also notes that there is no standardization among the different methods of analysis and this "implies that much depends on the subjective interpretation and skill of the individual" performing the analysis. Vrij attributes this to an absence of theoretical underpinning behind SCAN/statement analysis. Vrij characterizes SCAN/statement analysis as weaker than CBCA because SCAN/statement analysis lacks "a set of cohesive criteria," being instead "a list of individual criteria." Vrij argues that SCAN/statement analysis is best used as a technique to guide investigative interviews rather than as a "lie detection tool."

Critics argue that the technique encourages investigators to prejudge a suspect as deceptive and affirm a presumption of guilt before the interrogation process has even begun. Statement analysis in general has been criticized as "theoretically vague" with little or no empirical evidence in its favor, and SCAN in particular has been characterized as "junk science" with the Skeptic's Dictionary and Skeptical Inquirer magazine classifying it as a form of pseudoscience.