Today is pi day here in the United States, where we list the date before the month in our date shorthand, thereby enabling geeks to celebrate our geekiness on 3/14 each year. This year it’s extra special: 3/14/15 at 9:26:53 celebrates the first nine decimal places of pi.

It’s only fitting that today’s entry for Women’s History Month celebrate a female mathematician, and until earlier today, I didn’t even know the person I’m writing about was a mathematician. Florence Nightingale is of course more well-known for her pioneering work in nursing; her professionalization of the role (nurses were previously without training), management of hospitals, and attention to sanitary conditions, so transformed medicine that she is known as the founder of modern nursing. She was also a social reformer on issues including education, poverty, prostitution, and (despite her generally low opinion of women) the expansion of women’s professional opportunities. However, hand in hand with these accomplishments goes her work in the field of statistics: she believed that public policy should be based on data, and she had the skill and training in mathematics to present data in vivid and accurate forms.

Paul Lewi calls her “one of the pioneers of modern statistics.”

She . . . insist[ed] that statistics should be used and understood by politicians and officials as a rational means for decision making. To this effect she designed original diagrams which illustrated in a dramatic way the needless sacrifice of human lives and the simple means to prevent it. These diagrams were
published as part of the many reports and proposals that she prepared on various issues including health care, education, child labor, work houses and crime.

Her work in the Crimean War went far beyond her admirable service as “the Lady with the Lamp”; she documented, and presented in then-new and convincing graphic form, the causes of death among the British Army. Eschewing the philosophy that was urged on her of “the dryer the better,” or the bar chart that was then popular but would not have conveyed the comparison between the same months in different years, she devised a complex variation on the pie chart now known as the “Nightingale Rose.”


(An animation of this chart can be viewed here.)

Nightingale went on to use “applied statistics”–a term she coined, according to Lewi–to drive policy changes in public health in India and at home in England. All of this was possible because her talent as a mathematician was recognized and nurtured beginning in her earliest years. So have a piece of pie for pi day, improved pie charts, and a woman who saved thousands of lives or more.