The full content of Annals is available to subscribers

Subscribe/Learn More  >
History of Medicine |

100 Apples Divided by 15 Red Herrings: A Cautionary Tale from the Mid-19th Century on Comparing Hospital Mortality Rates

Lisa I. Iezzoni, MD, MSc
[+] Article, Author, and Disclosure Information

From Beth Israel Hospital, Boston, Massachusetts. For the current author address, see end of text. Acknowledgments: In a brief overview of Nightingale's contribution to examining outcomes of care, I fell into the trap of seizing her “bottom line” on hospital mortality rates without investigating her methods. Duncan Neuhauser, PhD, alerted me to my failing and kindly pointed me to sources that revealed the full story. I thank Dr. Neuhauser for his gentle rebuke and for giving me a rich opportunity to investigate and learn the lessons of history. I also thank Kristin Miller, who scoured the Countway Medical Library Rare Books Room and the Harvard University libraries, for her assistance in this research. Requests for Reprints: Lisa I. Iezzoni, MD, MSc, Division of General Medicine and Primary Care, Department of Medicine, Beth Israel Hospital, 330 Brookline Avenue, Boston, MA 02215.

Copyright ©2004 by the American College of Physicians

Ann Intern Med. 1996;124(12):1079-1085. doi:10.7326/0003-4819-124-12-199606150-00009
Text Size: A A A

In 1863, Florence Nightingale argued that London hospitals were dangerous, especially compared with provincial facilities.She bolstered this contention with statistics published in William Farr's Registrar-General report, which claimed that 24 London hospitals had mortality rates exceeding 90%, whereas rural hospitals had an average mortality rate of 13%. Farr had calculated mortality rates by dividing the total number of patients who died throughout the year by the number of inpatients on a single day. When calculated as the annual number of deaths divided by the total number of inpatients during the year, the mortality rate of London hospitals was 10%. A raucous debate erupted in the London medical press over how best to calculate hospital mortality rates. Critics claimed that Farr had not adjusted for differences in severity of illness between urban and rural hospitals and that his figures would mislead the public. Farr and Nightingale, in turn, criticized the poor quality of hospital data. This story reinforces the need to understand the methodologic derivation of statistics intended to compare provider quality.


Grahic Jump Location
Figure 1.
Table publishedin the third edition of Florence Nightingale's Notes on Hospitals[9]


Grahic Jump Location




Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).


Submit a Comment/Letter
Submit a Comment/Letter

Summary for Patients

Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.


Buy Now for $32.00

to gain full access to the content and tools.

Want to Subscribe?

Learn more about subscription options

Topic Collections
Forgot your password?
Enter your username and email address. We'll send you a reminder to the email address on record.