The problems presented by dependency groups have become a key issue for health care and social policy in all advanced countries. Providers and policy makers have looked to researchers to develop and apply measures of dependency which will provide a basis for rational planning and service provision. Attempts to define and classify dependency are notable by their absence from the empirical literature. This paper offers a general definition of dependency and develops a classification system based on needs for help and the sources of these needs. Existing measures tackle only a very limited range of problems within this matrix. Issues of reciprocity and dimensions of severity are dealt with separately before considering the implications of this discussion for future research.
