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Tuesday, May 12, 2020

Florence Nightingale: Innovator in Statistics and Data Presentation

I learned as a child about Florence Nightingale (1820-1910) as the founder of the modern profession of nursing and probably the single person who did the most to make it socially acceptable for women from middle- and upper-class background to become nurses. Her name became eponymous: referring to someone as "Florence Nightingale" was a way of saying that the person was a perfect nurse. For more than a century, the International Committee of the Red Cross has given an award in her name for "exceptional courage and devotion to the wounded, sick or disabled or to civilian victims of a conflict or disaster" or "exemplary services or a creative and pioneering spirit in the areas of public health or nursing education."

What I had not learned about Nightingale as a child was that she was also an early innovator in applying statistical analysis to health data, and in the graphic presentation of data.  Indeed, he was the first female member of Britain's Royal Statistical Society/  Noel-Ann Bradshaw provides a nice overview of this story in "Florence Nightingale (1820–1910): An Unexpected Master of Data," in Patterns magazine (May 2020). 

Nightingale's work in statistics and data followed after her legendary work in the Crimean War. (For background here, I draw on the article about Nightingale from the History.com editors, updated April 17, 2020.)  When she arrived at the main British base hospital in Constantinople in 1854, she found that the "hospital sat on top of a large cesspool, which contaminated the water and the hospital building itself. Patients lay on in their own excrement on stretchers strewn throughout the hallways. Rodents and bugs scurried past them. The most basic supplies, such as bandages and soap, grew increasingly scarce as the number of ill and wounded steadily increased. Even water needed to be rationed. More soldiers were dying from infectious diseases like typhoid and cholera than from injuries incurred in battle."

Nightingale dramatically revamped hygiene, food, laundry, and nursing practices. The hospital's death rate fell by two-thirds. Upon her return to England in 1856, she was greeted as a hero. She wrote an 830-page report, "Notes on Matters Affecting the Health, Efficiency and Hospital Administration of the British Army." Queen Victoria supported her in establishing Royal Commission for the Health of the Army in 1857. where she worked with leading statisticians of the day. 

Bradshaw presents several examples of Nightingale's data presentations. For example, Bradshaw writes: 
She became fascinated that the mortality rate among soldiers stationed at home was higher than the mortality rate of ordinary British men, despite soldiers being healthier at the start of their careers. She used data to examine the cause, concluding that the problem was poor sanitation and over-crowding of military barracks, encampments, and hospitals that exacerbated the spread of disease. She drew many graphs depicting this, including Figure 1, which shows five circles filled with hexagons representing the space between people. The first three circles show how closely packed the army would be in the Quartermaster General’s camp plans, while the last two circles show how densely packed the inner city of London currently was and the population of London in general. This comparison made it obvious to anyone that the Quartermaster General’s proposition for encampment was going to be problematic given how unhealthy densely populated areas of London were.
Figure thumbnail gr1

Here's another example, from Bradshaw:
She [Nightingale] went on to forecast the efficiency of the army if the soldiers were as healthy as the rest of the men in the UK. This graph was way ahead of its time (Figure 2). On the left she displayed the current situation, showing the effectiveness of the British Army in terms of the numbers who were ill, invalided, etc. On the right she graphed the potential effectiveness of the army if the soldiers were as healthy as the general male population. By forecasting this potential effectiveness, she emphasized how the army at rest were experiencing higher degrees of mortality that the general male population.
Figure thumbnail gr2
Perhaps the most famous of Nightingale's figures was sometimes called the "rose" diagram. Each wedge represents death sin a month. The red part of the wedge is deaths from wounds; the blue par is deaths from infectious disease; and the total is deaths from all causes. The circle on the right is April 1854 to March 1855, while the circle on the left is the following year from April 1855 to March 1856. 

Figure thumbnail gr3

Exercises like these also made Nightingale an outspoken advocate for improved and regularized methods of collecting health statistics--a lesson which is self-evidently still being learned today during the coronovirus pandemic. 

I should be clear that Nightingale's work in statistics and data presentation has been well-known for a long time--just not by me. Indeed, there is an award given to a prominent female statistician every other year by the Committee of Presidents of Statistical Societies and Caucus for Women in Statistics called the Florence Nightingale David Award. F.N. David's (1909-1993) parents were friends with the nurse, and named their daughter after her. David did her doctoral research with Karl Pearson in the 1930s, and then spent most of of her professional career at University College in London,  University of California, Riverside, and University of California, Berkeley.

If history of data display is holding some perhaps unexpected appeal for you, you might also be interested in "William Playfair: Inventor of the Bar Graph, Line Graph, and Bar Chart" (August 9, 2017).