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Evaluating the Quality of Health Care

5. Outcome Measures

There is a long history of using outcomes to assess care quality. The use of outcome data to evaluate health care dates back more than 150 years. In the 1830s, a physician named Pierre-Charles-Alexandre Louis started a group in Paris that discussed the use of statistics to examine patterns of medical care and outcomes. In 1838, a physician from that group named George Norris returned to the United States and examined the survival of patients who had an amputation. In subsequent work Norris compared surgery outcomes at the Pennsylvania Hospital with those of hospitals in other cities and counties (Cassedy, 1984). During the same period, Florence Nightingale developed innovative ways of presenting statistics to illustrate seasonal variations in patient mortality in the military field hospital she managed. She later used similar techniques to describe the conditions of medical care in the Crimean War (Bostridge, 2008). Later, Codman used information about outcomes from medical records at the Massachusetts General Hospital in Boston to assess the quality of care provided by different surgeons (Codman, 1914; Neuhauser, 1990).

To use medical outcomes as a quality measure, one must usually calculate rates of certain outcomes for a group of patients since outcomes are determined by many factors and thus one usually assesses whether the probability of death, for example is higher or lower for one group compared to another. One could also develop explicit a priori criteria to determine whether the observed results of care are consistent with the outcome predicted by a model that has been validated on the basis of scientific evidence (Brook, McGlynn, & Cleary, 1996). For example, one might assess if the population of patients with diabetes and specific clinical characteristics are better or worse than expected.

Cassedy, J. H. (1984). American Medicine and Statistical Thinking, 1800-1860. Cambridge, MA: Harvard University Press.
Bostridge, M. (2008). Florence Nightingale. The Making of an Icon. New York, NY: Farrar Straus and Giroux.
Codman, E. A. (1914). The product of a hospital. Surg, Gynecol, Obstet, 18, 491-496.