David Cox was a statistician who significantly advanced statistical analysis and its application. His paper introducing his proportional hazards model has some tens of thousands of citations. The best known application of this work is in analysing data from clinical trials; other applications include modelling failure of mechanical components.
David's model provides a means to work out which of many possible variables are predictive of a particular outcome that is related to the time that has passed. David's many other notable contributions included detailed studies of sequences of point events and work on experimental design.