Colorado residents may be surprised to learn that a controversial technique considered to be even less reliable than polygraph testing is popular with law enforcement agencies across the country. Scientific Content Analysis, or SCAN, involves analyzing the written answers that criminal suspects provide to a series of questions, and even those who perform SCAN evaluations concede that their trust in the technique is based more on faith than on science.

Like the results of lie detector tests, SCAN evaluations are not admissible in court because they are considered unreliable. However, that has not stopped at least 417 law enforcement and military agencies in the United States from purchasing and using the technique. Police use SCAN to narrow down a list of possible suspects and focus their investigations, but civil rights groups worry that innocent people are being charged and prosecuted largely based on the words they used in a written test.

The company that develops and sells SCAN products to police departments and federal agencies claims that the technique can separate fact from deception about 95% of the time, but the firm provides no empirical evidence to back up this claim. Studies that have been performed by academics who published their findings in peer-reviewed scientific journals have concluded that SCAN is about as accurate a predictor of truth as a coin toss.

Individuals who have nothing to hide may believe that it is in their best interests to cooperate fully with the police, but experienced criminal defense attorneys would likely have a different opinion. Police rarely interrogate suspects unless they are considering criminal charges, which is why attorneys may advise any person who is detained by law enforcement to remain silent and ask for a lawyer. Attorneys might object to the use of unreliable techniques like SCAN evaluations and polygraph tests, and they may also work to ensure that rights protected by the U.S. Constitution are not violated.