Circular error probable

Circular error probable (CEP) is a measure of a ballistic missile's accuracy. CEP is the radius at which a missile has a 50% chance of hitting. For example, the Minute Man III missile has a CEP of 200 to 250 meters. This means that if you draw a circle of radius 200-250m, you will be able to hit it with a warhead from a Minute Man III missile 50% of the time.