- Harlan M Krumholz, Harold H Hines Jr professor of medicine1,
- Zhenqiu Lin, senior biostatistician2,
- Sharon-Lise T Normand, professor of healthcare policy (biostatistics)3
- 1Yale University School of Medicine, New Haven, CT 06510, USA
- 2Center for Outcomes Research and Evaluation, Yale-New Haven Hospital, New Haven, CT, USA
- 3Department of Health Care Policy, Harvard Medical School, Boston, MA, USA
The proliferation of information about hospital performance is a cause for consternation. We are drawn to data about performance, yet we are wary of their accuracy and reliability. We want information about the results that our acute care organizations achieve, yet we are often skeptical about whether what is important in medicine can be measured well.
Among the measures, those related to outcomes have taken center stage.1 Outcomes measures can fully capture the end result of healthcare; they can include all patients within a diagnostic category or even across an institution. In the United States these measures have financial consequences as a result of federal legislation.2 3 4 5 Consequently, hospitals and others affected by outcomes measures have focused intently on the validity of the methods that underlie these metrics.
The most common hospital outcomes measures use standardized outcome ratios, generally an observed value divided by an expected value (for example, observed mortality divided by expected mortality). The approach is intended to quantify how a hospital performs relative to other hospitals, after considering differences in case mix and sample size. The product is a ratio of whether …