Outcome measurement: concepts and questions.

Outcome measurement-a central concept of quality of care-has both conceptual appeal and limitations as a practical assessment tool. The degree to which outcomes can be directly related to processes of care continues to be especially problematic. I view the continued debate about whether processes or outcomes are the preferable measure of quality as fundamentally unproductive, because both are needed. To strengthen our understanding of both measures in ascertaining quality of care, I suggest that work in four areas is needed: more definitive evidence of process and outcome linkages; stronger relationships between technology assessment and quality assessment; improved reliability and validity of outcome measures as screening tools; and continued development of health status measures.