This paper introduces and discusses the fundamental concepts of a theory for the efficient assessment of the operating state of an organization within a given period of its existence. The discussed approach is an extension of the knowledge space theory (Doignon & Falmagne, 1985) to the organizational field. According to the suggested theory, the organizational process of a given class of organizations can be decomposed into a set E of organizational events, viewed as discrete units of time. This set is called "domain of action" of a class of organizations. The "operating state" of a single organization is the set A of all events in E that have occurred at least once in that organization. An "action structure" is the collection of all the operating states that can be observed within a given population of organizations. According to the suggested approach, an action structure is a formal model of the organizational process. The construction of an action structure relies upon the assumption that the organizational events are related to each other on the basis of two binary relations: a "prerequisite relation", and an "exclusion relation". Some of the procedures for the practical construction and empirical test of an action structure are discussed. The final section is an overview of some procedures for the efficient assessment of an organization by means of action structures.