[Epidemiology and assessment of health care services: new research trends]

This article begins by analyzing the difficulty that Clinical Medicine, Epidemiology, and Health Planning and Administration have in dealing with the dynamic, complex social dimensions characterizing the technological organization of the diagnostic and therapeutic process, necessary for the production of health services' knowledge about diseases, a difficulty which has become more evident with the increasingly frequent and varied assessments in health care. The latest tendencies in "health services research" are analyzed, along with a priorization of effectiveness and outcomes, seeking to respond to the identified problems through a redefinition of objects and methodologies.