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Matthew Barsalou

Six Sigma

Florence Nightingale Could Have Donned a Six Sigma Black Belt

Her healthcare reforms are as legendary as DMAIC

Published: Thursday, November 29, 2012 - 13:16

Six Sigma was originally created by Bob Gavin at Motorola during the 1980s; however, it could be argued that a comparable methodology was in use as early as the 1850s. Florence Nightingale is known for founding the field of nursing, but few people outside of the field of mathematics appreciate her contributions to statistics during the Crimean War.

 To support Turkey in a war against Russia, England and France had invaded the Crimean peninsula. According to Bernard Cohen’s fascinating article, “Florence Nightingale” (Scientific American, March 1984), the French had sent nurses to care for their wounded while British troops did not even have material to make bandages. Nightingale went to the Crimea to train and lead a group of nurses at the Scutari military hospital.

In his December 2003 Quality & Safety in Health Care article, Florence Nightingale Gets No Respect: As a Statistician That Is,” Duncan Neuhauser notes that Nightingale arrived to find a mortality rate of 42 percent. The hospital was filthy, and the wind was blowing air out of the sewers and into the areas with patients. Laundry was washed in cold water, and many supposedly clean blankets needed to be destroyed because they were still infested with parasites after washing.

It seems the military would have been glad for any help; however, as Nightingale tried to implement changes, the military attempted to block her. They feared “any change might seem to be a concession of their own errors or incompetence,” writes Cohen. It probably didn’t help that she was woman, he adds. There was even a time when Nightingale’s nurses were banned from going into the wards with the wounded. Another time a military supply officer refused to release urgently needed shirts until the entire shipment of 27,000 shirts had been inspected. In spite of such obstructions, Nightingale went on to push for a reform of the British military hospital system because of her experiences in the Crimea. She did this in a way that would be familiar to a Six Sigma Black Belt.


Six Sigma uses a strategy called define, measure, analyze, improve, control (DMAIC). During the define phase a problem gets defined based on the voice of the customer, and a goal is established. The problem Nightingale wished to address was mortality caused by unsanitary conditions in hospitals; her objective was to reduce the mortality rate. The soldiers dying in the hospitals can be viewed as customers. Nightingale consulted with William Farr, who was a statistical expert. He served in a role comparable to a Six Sigma Master Black Belt. 


During the measure phase, measurements are made to establish a baseline for improvement. Nightingale determined London hospitals had 1,600 square feet per patient, and the Scutari hospital only had 300 to 500 square feet per patient. The death rate for patients at Scutari was found to be 42.7 percent. Nightingale created surveys to gather data and used graphs to present her data. She also invented polar-area diagrams (shown below), which could show mortality by type, location, and time.

Click here for larger image.


Nightingale was aware that simply having data was insufficient for implementing improvements. The data had to be usable and controlled for confounding. Upon receiving data that supposedly proved her reforms were not effective, Nightingale observed the procedures were not uniformly implemented. Also the data on hospitals with her reforms was mixed with data on hospitals without her reforms.

Lynn Mcdonald writes in “Florence Nightingale and the Early Origins of Evidence Based Nursing” (Evidence Based Nursing, 2001), about Nightingale’s notes on the data. “Much injury has been done to the cause by putting forward figures at all as a test of nursing efficiency,” she noted. “Hospital statistics represent first and primarily the effects of the sanitary state of the hospital... next the severity of the cases. After this is determined they represent the result of different operations and different modes of treatment, and after all these constants are determined they may represent the dieting, nursing, and general management, but in your Liverpool case they represent nothing, because they have never been kept with reference to any result.” 


Based on her data, Nightingale implemented many improvements. For example, in April 1855 hundreds of carts filled with filth were removed from the hospital at Scutari, and the sewers were cleaned out. Dead horses, dogs, and a cow were removed from the hospital grounds.

Because of Nightingale, a royal commission formed subcommissions responsible for carrying out procedures such as providing clean ventilation in hospitals and military barracks, and improving water and waste sanitation. Also procedures were implemented for gathering medical statistics related to the military.

According to Neuhauser, the reforms implemented by Nightingale reduced the death rate from 42.7 percent of all patients admitted at Scutari to 2.2 percent within only two months. The head medical officer for the Army claimed the improvements were the results of healthier soldiers coming into the hospital, so Nightingale compared the death rate of soldiers too wounded to be transported to the hospital. The severely wounded died at a rate of 2.7 percent, and the healthier hospitalized soldiers died at a rate of 42.7 percent.

Prior to Nightingale’s improvements, severely wounded soldiers had a better chance of surviving by staying in the battlefield than the less severely wounded who were transported to the hospital. With Nightingale’s improvements, the death rate at Scutari was actually lower than the death rate at military hospitals in London. It was this data that convinced the government of the validity of Nightingale’s reforms.


The effectiveness of Nightingale’s improvements was easy to verify. Nightingale knew her efforts in the Crimea had paid off because the death rate for wounded soldiers in the Crimea was only slightly higher than the death rate for healthy soldiers in England. More astonishing was that the overall death rate for soldiers in the Crimea was only two-thirds of what it was for troops stationed in England.

The case of Florence Nightingale also illustrates that some things have not changed after a century and a half: Statistical evidence may be needed to convince a skeptical management that changes are both necessary and effective.


About The Author

Matthew Barsalou’s picture

Matthew Barsalou

Matthew Barsalou is a statistical problem resolution master black belt at BorgWarner Turbo Systems Engineering GmbH. He is an ASQ-certified Six Sigma Black Belt, quality engineer, and quality technician; a TÜV-certified quality manager, quality management representative, and quality auditor; and a Smarter Solutions-certified lean Six Sigma Master Black Belt. He has a bachelor’s degree in industrial sciences, and master’s degrees in engineering, business administration, and liberal studies with emphasis in international business. Barsalou is author of Root Cause Analysis, Statistics for Six Sigma Black Belts, The ASQ Pocket Guide to Statistics for Six Sigma Black Belts, and The Quality Improvement Field Guide.