- Ecological fallacy
The ecological fallacy is a widely recognized error in the interpretation of
statistic al data in anecological study , whereby inferences about the nature of individuals are based solely upon aggregate statistics collected for the group to which those individuals belong. Thisfallacy assumes that individual members of a group exhibit characteristics of the group at large. Stereotypes are one form of ecological fallacy. We are guilty of the ecological fallacy when we infer characteristics about an individual from the known characteristics of the group to which the individual belongs. When we commit the ecological fallacy we are assuming that groups are homogeneous. In other words, just because a particular group of people might have a lower average IQ than the general population that does not mean that *all* members of that group have a lower IQ than the general population. Thus, if we were to select an individual from that group, we cannot know if that person has a lower than average IQ, average IQ, or above average IQ even though we know that that group of individuals has a lower average IQ.Examples and case study
Examples
A study is done that shows people from City A score higher on the
SAT s, on average, than people from City B. Making an assumption that a randomly selected individual from City A would have scored higher on the SATs than a randomly selected individual from City B would be an ecological fallacy. Since the SAT scores given in the study were an average, it is indeed possible that the individual from City A scored in the bottom ten percent on the SATs and the individual from City B just happened to score in the top ten percent.If a particular sports team is described as performing poorly, it would be fallacious to conclude that each player on that team performs poorly. Because the performance of the team depends on each player, one excellent player and two terrible players may average out to three poor players. This does not diminish the excellence of the one player.
Case study
The ecological fallacy was a factor in the judge's decision to uphold the election of
Christine Gregoire in the court challenge to theWashington gubernatorial election, 2004 . The challengers had attempted to argue that illegal votes cast in the election would have followed the voting patterns of the precincts in which they had been cast, which they contended would have favored Gregoire. The judge determined that this constituted an ecological fallacy, and disallowed the evidence. An expert witness for Gregoire explained the ecological fallacy as trying to figure out Ichiro Suzuki's batting average by looking at the batting average of the entire Seattle Mariners team. [http://www.tri-cityherald.com/tch/local/state/v-printer/story/6580281p-6463857c.html]Origin of concept
The term comes from a 1950 paper by William S. Robinson. [cite journal|author=Robinson, W.S.|year=1950|title=Ecological Correlations and the Behavior of Individuals|journal=American Sociological Review|volume=15|pages=351–357|doi=10.2307/2087176] For each of the 48 states in the US as of the 1930 census, he computed the literacy rate and the proportion of the population born outside the US. He showed that these two figures were associated with a positive correlation of 0.53 — in other words, the greater the proportion of immigrants in a state, the higher its average literacy. However, when individuals are considered, the correlation was −0.11 — immigrants were on average less literate than native citizens. Robinson showed that the positive correlation at the level of state populations was because immigrants tended to settle in states where the native population was more literate. He cautioned against deducing conclusions about individuals on the basis of population-level, or "ecological" data.
Inverse error
Hasty generalization is the opposite of the ecological fallacy. It occurs when one makes a generalization about a group based on insufficient data. For example, if one made a generalization about an entire group based only on a few members of that group, then one would be making a hasty generalization.ee also
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Ecological correlation
*Modifiable areal unit problem
*Prosecutor's fallacy
*Sampling (statistics)
*Simpson's paradox
*Statistical discrimination References
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