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Ask Professor Rosenthal 3 – Woodpeckers, Woodknocking, and Critical-Thinking


Author(s): Scott Douglas Jacobsen

Publication (Outlet/Website): Canadian Atheist

Publication Date (yyyy/mm/dd): 2019/05/21

Dr. Jeffrey S. Rosenthal is a Professor of Statistics at the University of Toronto. Here we talk about critical thinking and Knock on Wood.

Scott Douglas Jacobsen: When an ordinary citizen like myself or someone else comes across a piece of information, what are some important critical questions to ask about it?

Professor Jeffrey S. Rosenthal: First of all, what is the source of the information, and is it accurate? But accuracy is only a first step. 

Often facts are quoted correctly, but out of context, so that they give misleading impressions.  It’s always important to think of the bigger picture, and whether the information really means what they claim it means.

Jacobsen: What are some tips and tricks of statistical interpretation to keep in mind to avoid being lied to and mislead?

Rosenthal: In my book Knock On Wood, I talk about various “luck traps”, which lead us to draw false conclusions.  Many of them are related to what I call the “out of how many” principle. 

Perhaps you hear some striking fact, like two people meeting up in the most unexpected place or having incredible similarities. You should always ask, this one fact occurred out of how many people? 

Out of how many pairs of people? Out of how many different places where it could have happened? Out of how many times that it didn’t happen?  Out of how many other equally surprising things which could have happened but didn’t? 

Such questions give a broader perspective, and often show that it wasn’t so unexpected that the occurrence, or some similar such occurrence, would have occurred at some point to some people in some place at some time.

Jacobsen: What are common manipulations built on misrepresenting statistics to us, in politics and in pseudoscience?

Rosenthal: Even if no misrepresentation is intended, selectively quoting facts can be quite misleading.  But if the intention is to misrepresent, then the problem only gets worse. 

Often it takes the form of “cherry picking”, where someone quotes one particular fact while hiding the bigger picture.  For example, perhaps a politician points out how one new factory was built, without mentioning several others which closed. 

Or an “alternative” medical practitioner describes in detail how one patient was saved by their methods, covering up several other patients who tried their methods but died. 

So, in addition to worrying that you’re not getting the whole story or that the facts aren’t accurate, you should also worry that the person providing the facts might not have truth and balance as their objective and might intentionally mislead you.

Jacobsen: Thank you for the opportunity and your time, Professor Rosenthal.


In-Sight Publishing by Scott Douglas Jacobsen is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. Based on a work at


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