Logically Fallacious: The Ultimate Collection of Over 300 Logical Fallacies (Academic Edition) (Dr. Bo's Critical Thinking Series)

by Bo Bennett

Post-Designation (also known as: fishing for data) Description: Drawing a conclusion from correlations observed in a given sample, but only after the sample has already been drawn, and without declaring in advance what correlations the experimenter was expecting to find. Logical Form: A sample from a dataset is drawn. A correlation is found that was not looked at nor is it statistically surprising. The correlation is seen as being meaningful. Example #1: In looking at the records of my students, I have found that 9 out of 10 are an only child. Therefore, society is moving towards one-child families. Explanation: When you start looking at data with no expectations, anything goes, and any data due to random, statistical anomalies will stand out as “odd.” In this case, the fact that 9 out of 10 kids don’t have siblings is outside of the norm, but that is the nature of probability. If you were hypothesizing that most kids don’t have siblings, and you found this data, then it would provide more of a reason to do further research in making a more justified conclusion.