Florence Nightingale

Nightingale organized nursing care for British soldiers during the Crimean War and, on return, analyzed the army's own mortality records to show that far more soldiers had died of preventable disease in unsanitary field hospitals than of wounds from combat. To make the finding legible to officials who would not read a table, she designed the polar area diagram, a circular chart now often called a Nightingale rose, where the area of each wedge shows the death toll by month and cause, letting a reader see at a glance that disease dwarfed battle deaths. She became the first woman elected a fellow of the Royal Statistical Society, and the sanitary reforms her report drove cut military hospital mortality sharply in the years after.