National Institute for Truth Verification produces the CVSA, first introduced in 1988. The company advertises that this device was developed from the Psychological Stress Evaluator (PSE) and is widely distributed amongst law enforcement agencies. Examiner certification is required. The CVSA testing format is dissimilar to PDD formats. Like other voice-based deception detection systems, published scientific research has failed to find any accuracy with the CVSA. See Psychological Stress Evaluator (PSE) and voice stress analysis.