Though the concept of hierarchy has been used extensively in the siting of multilevel service systems, particular attention has not been paid by analysts to the full variety of ways in which locational goals of different service levels can be linked. Many past studies of locational hierarchies, for example, have been merely structural elaborations of common single-level location problems, with little thought given to the way in which service goals can or should be linked.The purpose of this analysis is to develop multilevel siting models which incorporate spatial expressions of the functional interdependence between service levels. More importantly, however, this paper suggests the necessity for differentiating between two broad categories of hierarchical location systems, those which are <I>technologically linked</I> and those which are <I>behaviorally linked</I>. The basis of this differentiation is the type of spatial information which is communicated from one organization level to another. Furthermore, these two types of hierarchical systems are shown to have locational goal structures which can be exploited effectively in various planning scenarios.
