[Family diagnosis and evaluation research].

Investigations are presented examining the reliability and validity of family-diagnostic methods which have served to evaluate family therapy or might be used for this purpose, respectively. The central result of these investigations has shown that even common instruments for assessing the family system, its internal structure or the way it is interconnected with larger social systems rarely prove to be sufficiently reliable and even more seldom satisfactorily valid. The significance of the results for theory and practice is discussed.