It is becoming increasingly important, in the administration of psychiatric units, to single out the likely absconder from the rest of the hospital community. The following study has been embarked upon partly to outline a sketch of a hypothetical absconder, and partly to lay down a method of study which could be applied to other institutions with similar problems. The problem of absconding is of comparatively recent origin, as the “open door policy” has become generally adopted in British mental hospitals.