How to lie with statistics - Trick #2: Claim causality
Monday, June 29th, 2009(If you go “Lying with statistics is unethical - what is this?” then read the intro)
A comonly used way to misuse statistics, is to claim causality between two entities of which a relation has been demonstrated. For example
a) If people eating apples have longer live expectancy, then present the results as if it was because of the apples. The truth may be that people eating apples are more likely to do more exercise, but that concern won’t sell your apples, right?
b) If people wearing a tie have higher average income, then you can claim it was because of the excelent silk ties you are selling. The truth probably is that people wearing a tie have made other carrier choices from early on in their life, but never mind.
In case you want to counter a causality claim, remember that NO data, NO statistics and NO mathematics can formally imply causality. Causality is the result of scientific theories or everyday comon sense. Thus, if the reason for one entity causing another is not clear, it is probabily just a wild guess of the authors.