PPPP Change Theory is mainly an organizational change theory. It is also rational economic theory in that it lends itself to economic analyses using concepts of opportunity costs. From another important perspective, PPPP Change Theory can be cast in the logic of game theory, and game theory mathematics can be used in testing it. The basic difference between public police and private police is that public police belong to commonweal organizations and private police are business concerns. The mechanisms that determine when private police are created and used and when public police are created and relied on are largely economic and related to the crime rate; this fact is most important in PPPP Change Theory. PPPP Change Theory maintains that private security will change more rapidly in response to changes in either crime rate or affluence than will public police. Using a refined statistical model to analyze past data might be a way to test PPPP Change Theory. Photographs and 15 references