The Research Methods Knowledge Base website reminds us researchers (and readers of research findings) of the “Two Research Fallacies”.
“A fallacy is an error in reasoning, usually based on mistaken assumptions”.
The two most serious research fallacies discussed in this article are the “ecological fallacy” and the “exception fallacy”
“The ecological fallacy occurs when you make conclusions about individuals based only on analyses of group data”. For example, if the average income of a group of people is $60,000, we could not single out any individual and describe him or her as a $60,000 income person just because the group average is $60,000. It could be that this chosen individual is at either the lower or upper limited of the specific group. Always be careful not to make assumptions about individuals only based on the aggregate data for a group of individuals.
“An exception fallacy is sort of the reverse of the ecological fallacy. It occurs when you reach a group conclusion on the basis of exceptional cases. This is the kind of fallacious reasoning that is at the core of a lot of sexism and racism. The stereotype is of the guy who sees a woman make a driving error and concludes that “women are terrible drivers. Wrong! Fallacy!”
Don’t fall in the traps of fallacies when interpreting research findings. In addition to summary data (e.g. means and averages), we need to be aware of individual differences within the analysed group.
The Research Methods Knowledge Base: http://www.socialresearchmethods.net/kb/fallacy.php (accessed September 2, 2012)