Definitions for "Ecological Fallacy"
A mistake based on believing that what is true for a group must also be true for each individual in the group.
The problem of inferring characteristics of individuals from aggregate data referring to a population; equivalently, the problem of inferring individual household characteristics using areal unit (spatial) data (Johnston et al. 1994; Wrigley et al. 1996).
The inference that a correlation between variables derived from data grouped in social or other aggregates (ecological units) will hold between persons (individual units).