Statement analysis, also called investigative discourse analysis and scientific content analysis (SCAN), is a technique for analyzing the words people use to try to determine if what they said is accurate. Proponents claim this technique can be used to detect concealed information, missing information, and whether the information that person has provided is true or false.
Related to statement analysis is a different technique for analyzing the words people use called statement validity assessment, whose core phase is called criteria-based content analysis (CBCA). CBCA has been accepted as evidence in courts in Germany as early as 1954 but is typically not accepted by courts of other countries.
Proponents say statement analysis has proven effective as a police interrogation technique, but critics argue that it has not been subjected to objective analysis, with most of the studies failing to have used any outside criteria to confirm whether the statements were actually true or false. As it has not been proven experimentally and is generally unaccepted by courts, skeptics call it an example of pseudoscience.
Statement analysis involves an investigator searching for linguistic cues and gaps in a subject's testimony or preliminary statements. Ideally, the technique would guide investigators to ask follow-up questions to uncover discrepancies. The creator of Scientific Content Analysis (SCAN), Avinoam Sapir, gives the example of someone saying, "I counted the money, put the bag on the counter, and proceeded to go home." Sapir says the statement was literally true:
"He counted the money (when you steal you want to know how much you are stealing), and then the subject put the bag on the counter. The subject didn't say that he put the money back in the bag after counting it, because he didn't; he left the empty bag on the counter and walked away with the money." 
Sapir says that a fundamental principle of statement analysis is that "denying guilt is not the same as denying the act. When one says 'I am not guilty' or 'I am innocent,' they are not denying the act; they are only denying guilt." Sapir claims that it is almost impossible for a guilty person to say "I didn't do it." He asserts that guilty people tend to speak in even greater circumlocutions by saying things like "I had nothing to do with it" or "I am not involved in that."
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.
- Leo, Richard A. (2008). Police interrogation and American justice. Harvard University Press. ISBN 978-0-674-02648-3.
- Carroll, Robert T. (2009-02-23). "L.S.I. SCAN - Too Good To Be True". The Skeptic's Dictionary. Retrieved 14 September 2010.
- Adams, Susan H. (October 1996). "Statement Analysis: What Do Suspects' Words Really Reveal?". Polygraph Volume:25 Issue:4. pp. 266–278. Archived from the original on 21 September 2009. Retrieved 14 September 2010.
- Aldert Vrij, Detecting Lies and Deceit: Pitfalls and Opportunities, 2nd ed., Chichester, England: John Wiley & Sons, 2008, p. 290.
- Aldert Vrij, Detecting Lies and Deceit: Pitfalls and Opportunities, 2nd ed., Chichester, England: John Wiley & Sons, 2008, p. 291.
- "Statement Analysis Scan or Scam?," by Robert A. Shearer, Skeptical Inquirer, May/June 1999