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As my first introduction to the ecological fallacy, I thought it did a good job concisely stating the fallacy, with good examples to illustrate it (both intuiti
by SoftwareMaven 14y ago
As my first introduction to the ecological fallacy, I thought it did a good job concisely stating the fallacy, with good examples to illustrate it (both intuitive and non-intuitive).
The next question that would inevitably come up is: how do you know? I'm guessing there isn't a way short of looking at the data for individuals. It would probably be safe to always assume group data does not imply individual data.
And, of course, this is another way that people can use statistics to lie to you. I would not be surprised at all to find people intentionally using this fallacy to their benefit.
- glaugh 14y agoUnfortunately, I'm not aware of any good heuristics for identifying when the ecological fallacy is or is not an issue. As you suggested, that implies that one should always consider it to be an issue if the individual level data isn't available. Does anyone know of anything I'm missing here?
- ChuckMcM 14y agoRecommended reading "Proofiness: The Dark Arts of Mathematical Deception" by Seife. Talks about this fallacy and others in depth. The best approach is multi-variate analysis. Which is to say for each correlation you find, identify another correlation that would be true (and is measurable) if the cause was what you hypothesize is the cause. Its a great way to write a paper too. You start with "look at this correlation", we hypothesize that cause is "Q" and now we go look at the following correlations to prove or disprove our hypothesis, ... analysis and graphs ..., as you can see our hypothesis is thoroughly {proven | disproved} by these correlations. If the data isn't available to do additional analysis then you are stuck trying to collect that data somehow. You can end up with inconclusive results in that case.
- lejohnq 14y agoHere's another image for some intuition about what is going on: http://blog.statwing.com/wp-content/uploads/2012/12/ecological-fallacy.png http://blog.statwing.com/wp-content/uploads/2012/12/ecologic... You wouldn't be able to say anything with confidence about individuals without the individual data but this image helps me think about what individual data would be needed to back up or refute an inference based on group data. If you can find data within some groups and they show very little to no relationship for X and Y then it's a little more likely that you can use the group inference. But in any case watch out!
- goodcanadian 14y agoThe trick is to always keep in mind what the data explicitly says. There is a correlation between states with low average income and high percentage votes for Romney. The sample in this set is the state. It says nothing about individual people. You cannot make any conclusions whatsoever about how individual income relates to voting based on that correlation. It is a fallacy to even attempt to do so without more data.