The professional organizations made up of PDD professionals from law enforcement, government, and the private sector. Incorporated in 1966 in Washington, D.C., the APA resulted from the merger of several polygraph associations, including the Academy of Scientific Interrogation, the American Academy of Polygraph Sciences, the National Board of Polygraph Examiners, the International Association of Polygraph Examiners, and the International Association for Polygraph Research. It currently has about 2,800 members and is headquartered in Chattanooga, Tennessee.