Who emphasized the use of statistical methods and comparison groups in medicine?

• A. Edward Jenner
• B. John Snow
• C. Pierre Charles-Alexandre Louis
• D. William Farr

Answer: (C)

Using statistics and direct comparison of patient outcomes to judge whether a medical treatment works is a shift toward evidence-based practice. Pierre Charles-Alexandre Louis championed this approach, collecting data from many patients and comparing outcomes across different treatments to see what actually helped or harmed. He famously used his numerical method to show that aggressive bleeding did not improve survival, illustrating how data from groups can overturn traditional practices based on anecdote or authority. This emphasis on measuring results across groups laid the groundwork for evaluating therapies with evidence rather than lore.

Edward Jenner is remembered for pioneering vaccination, John Snow for linking cholera to contaminated water through careful mapping and observation, and William Farr for advancing vital statistics and standardized data collection. But the concrete use of statistics and comparison groups to assess medical treatments is most closely associated with Louis.