Florence Nightingale saved lives through data visualisation

During the Crimean War (1853–1856), Florence Nightingale collected mortality data from British military hospitals and created a pioneering 'polar area diagram' — sometimes called a coxcomb chart — showing that most soldier deaths came not from wounds but from preventable infections. She used the diagram to lobby Parliament and the War Office, making data compelling to politicians who would not read statistics tables. Mortality in the hospitals dropped from 42% to 2% following her sanitation reforms. She is now considered a founding figure of both modern nursing and data visualisation.

Source: Cohen, Florence Nightingale, Scientific American (1984)