Sidney Katz, MD: a new paradigm for chronic illness and long-term care.

Dr. Sidney Katz's legacy to the field of gerontology is internationally recognized as his success at developing standardized measures and processes, beginning with the activities of daily living index, for the functional assessment of older adults with chronic conditions necessitating long-term services and supports. That work served as the bedrock for his subsequent major accomplishments, which improved rehabilitation services through interdisciplinary team work and attention to the patient-family constellation; reformed the regulation of nursing homes, refocusing it on resident outcomes and quality of life; and promulgated the concept of active life expectancy as a new approach to measuring the quality of later life.