tl;dr When people conclude results from group-level data will tell you about individual-level processes, they commit the ecological fallacy. This is true even of the individuals whose data contributed to those group-level results. This phenomenon can seem odd and counterintuitive. Keep reading to improve your intuition. We need history. The ecological fallacy is closely related to Simpson’s paradox1. It is often attributed to sociologist William S. Robinson’s (1950) paper Ecological Corre...
