Monthly Archives: January 2015

The Passionate Statistician

Fig. 1 Portrait of Florence Nightingale

Almost everyone has heard of Florence Nightingale: the Nurse; very few people have heard about Florence Nightingale: the Statistician. Ironically, however, she is one of the most important statisticians to have ever graced the field. Yes, her improvements to sanitation were revolutionary, and surely saved countless lives, but how she was able to bring about those improvements was equally innovative.

Picture this: It’s 1855 during the Crimean War. The air is rank and humid, filled with the smell of blood and sulfur—the fresh, salty aroma of the adjacent Black Sea long forgotten. Although you are required to help care for the many wounded soldiers, you are also charged with collecting, accurately keeping, and even analyzing army mortality records.

After months of attending to these records and conducting your analyses, you are faced with an appalling, yet undeniable, truth: more soldiers are dying from poor sanitation than from combat. In fact, the mortality rates from disease are so great that “during the first seven months of the Crimean campaign, a mortality rate of 60 per cent. per annum from disease alone occurred, a rate of mortality which exceeded even the Great Plague in London…”[1]

Florence Nightingale (FN) believed that allowing 16,000 men[2] to die from causes that were easily prevented with improved sanitation was almost akin to murder, and it would be equally criminal to do nothing to prevent these needless deaths from happening again[3]. She also felt it was downright disgraceful, if not scandalous, for a nation that considered itself the epitome of civilization to be this neglectful of their sanitation policy[4]. Sadly, these poor sanitary conditions were not just associated with the battlefield. As the war ended and FN returned home, she found that army barracks and even the hospitals experienced equally appalling mortality rates from disease[5].

She knew sanitation policies needed to be improved. She knew her statistical analysis was the best tool she could use to convince others of this need. Yet, she also knew that she would have to develop a better way to convey her data to the general public. She realized that although the empirical evidence would easily convince those who knew how to read the data, publishing it in the traditional way would severely limit the amount of people who could actually utilize the information. A smaller group of supporters meant that it would take more time to bring about the necessary improvements, and more time meant that more people would die. No, if her campaign was to succeed, she needed to have something that enabled almost everyone to easily draw the same conclusion she had for herself: their nation’s sanitation methods were claiming more lives than their enemy’s artillery.

She decided to model her data as a graphical illustration, specifically as a Rose chart (also known as a Polar Area or Coxcomb chart).

FN 1858 Rose Chart Fig. 2 Nightingale’s 1858 Rose Chart that graphically illustrates mortality rates Text: The Area of the blue, red, & black wedges are each measured from the centre as the common vertex. The blue wedges measured from the centre of the circle represent area for area the deaths from Preventible or Mitigable Zymotic diseases; the red wedges measured from the centre the deaths from wounds; & the black wedges measured from the centre the deaths from all the other causes. The black line across the red triangle in Nov. 1854 marks the boundary of the deaths from all other causes during the month. In October 1854, & April 1855; the black area coincides with the red; in January & February 1856, the blue coincides with the black. The entire areas may be compared by following the blue, the red & the black lines enclosing them.

At the time, these illustrations were quite an extraordinary feat, and very few statisticians had previously attempted to use these representations. This is because if the statistician was not careful with their calculations, then the representations could very easily mislead the observer. In fact, even FN was mislead at one point. Her initial analysis of the army’s mortality records led her to conclude that it was malnutrition, and not sanitation, that was the major cause of death during the Crimean campaign[6].

As can be seen in this link here [7], a Rose chart consists of multiple wedges. These wedges are called sectors and each one represents a different category in one’s data. It is important to note that the individual value of each category is represented by the sector’s area and not the radius. This was actually what caused FN to misinterpreted her data at first, as she used the radius, instead of the area, to represent the value of each sector. Despite the fact that the calculations can make it tricky to accurately represent numerical data, the chart can, on-the-other-hand, simplify comparisons and enable observers to easily identify causation[8].

Florence Nightingale was a true devotee to both statistical analysis and improved health care. She was an innovative woman, who pioneered the means with which to effectively communicate statistics’ findings that describe social phenomena. She was both revered and admired by her compatriots in the field of mathematics, and her great admiration for statistics earned her the nickname, “The Passionate Statistician.”


[1] Pearson, Egon Sharpe, Maurice George Kendall, and Robert Lewis Plackett, eds. Studies in the History of Statistics and Probability. Vol. 2. London: Griffin, 1970.

[2] Nightingale, F. (1858) Notes on Matters Affecting the Health, Efficiency, and Hospital Administration of the British Army Harrison and Sons, 1858

[3] Nightingale, Florence. Letter to Sir John McNeill. 1 March 1857. Letter H1/ST/NC3/SU74, copy ADD MSS 45768 f29 of Florence Nightingale: The Crimean War: Collected Works of Florence Nightingale, Vol.14. Ed. Lynn McDonald. Ontario, Canada: Wilfrid Laurier Univ. Press, 2010. 498-500. Print.

[4] Nightingale, F. (1859) A Contribution to the Sanitary History of the British Army during the Late War with Russia London: John W. Parker and Son.

[5] Nightingale, Florence. Notes on hospitals. Longman, Green, Longman, Roberts, and Green, 1863.

[6] Cohen, I.B. The Triumph of Numbers: How Counting Shaped Modern Life, W. H. Norton, 2006.

[7] ims25. “Mathematics of the Coxcombs” Understanding Uncertainty,11 May 2008. Web. 18 Dec. 2014.

[8] Small, Hugh (1998). Florence Nightingale: Avenging Angel. Constable, London.

[9] Heyde, Christopher C., and Eugene Seneta, eds. Statisticians of the Centuries. Springer, 2001.

[10] Farr, William. Letter to Florence Nightingale. (1857-1912). MS.8033, Nos. 1-20. Florence Nightingale and William Farr Collection. The Wellcome Library, Archives. London. Print.

[Fig. 1] Wikicommons: Duyckinick, Evert A. Portrait Gallery of Eminent Men and Women in Europe and America. New York: Johnson, Wilson & Company, 1873.

[Fig. 2] Wikicommons: Public Domain