after she met statistician William Farr at a dinner party that autumn.
The two had very different backgrounds: Nightingale came from the
upper class, with a name reflecting her childhood in Tuscany, while
Farr had been raised in poverty in rural Shropshire, eventually
studying medicine before moving into medical statistics.[33]
When it came to population data in the 1850s, Farr was the man to
speak to. Alongside his work on outbreaks like smallpox, he had set
up the first national system to collate data on things like births and
deaths. However, he’d noticed that these raw statistics could be
misleading. The total number of deaths in a particular area would
depend on how many inhabitants there were, as well as factors like
age: a town with an elderly population would generally have more
deaths each year than a town full of young people. To solve this
problem, Farr came up with a new measurement. Rather than study
total deaths, he looked at the rate of death per thousand people,
accounting for things like age. It meant he could compare different
populations in a fair way. ‘The death-rate is a fact; anything beyond
this is an inference,’ as Farr put it.[34]
Working with Farr, Nightingale applied these new methods to data
from the Crimea. She showed that death rates in army hospitals were
much higher than wards in Britain. She also measured the decline in
disease after the health commissioners arrived in 1855. As well as
producing tables of data, she took full advantage of a new trend in
Victorian science: data visualisation. Economists, geographers and
engineers had increasingly used graphs and figures to make their
work more accessible. Nightingale adapted these techniques,
converting her key results into bar graphs and pie chart-like figures.
Like Snow’s maps, the graphics focused on the most important
patterns, free of distractions. The visuals were clear and memorable,
helping her message to spread.
In 1858, she published her analysis of health in the British Army as
an 860-page book. Copies were shipped to leaders ranging from
Queen Victoria and the Prime Minister to newspaper editors and
European heads of state. Whether looking at hospitals or
communities, Nightingale believed that nature followed predictable
laws when it came to disease. She said those disastrous early