Ecological fallacy
The ecological fallacy is a fallacy in social science in which, on the basis of aggregate data that depicts the characteristics of a collective, inadmissible conclusions are drawn about individual data.
"Ecological" here means "collective" and goes back to the urban ecology of the Chicago School . The term was coined in 1950 by the American statistician William S. Robinson (1913-1996).
Corresponding to Coleman's bathtub (macro-micro-macro scheme), connections between aggregate data variables ( macro level ) are interpreted in the same way as connections on the individual level ( micro level ). This often leads to incorrect results. The ecological fallacy is the result of the fact that easy-to-understand mean values are compared, for example the average age or the average ability of people, instead of the actual distribution of the individual measured values.
- Example 1: Assume that in one constituency 30% are Catholics (1: macro) and 30% are voters of a conservative party (4: macro), while in another constituency 50% are Catholics and 50% are voters of a conservative party. The postulated fallacy is: Catholics vote for conservative parties. But that doesn't have to be the case, because in extreme cases not a single voter from a conservative party could even be a Catholic. The following should be checked: (2: micro) Individual people are Catholics. → (3: micro) It is precisely these people who vote for a conservative party.
- Example 2: The distribution of wealth in a village and in a large city: The city dweller is on average richer than the village dweller. But very often the poorest city dwellers are poorer than the poorest villagers because the city has a center effect and attracts poor people (e.g. social institutions in cities, social network among the numerous homeless people who are already in the city anyway). Then, by accumulating great wealth among a small elite, it is even possible that most urban dwellers are poorer than the average or poor rural dweller.