Accused of a fallacy? Suspect a fallacy? Ask Dr. Bo and the community!

Quickly register to comment, ask and respond to questions, and get FREE access to our passive online course on cognitive biases!

one moment please...


(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.  This is related to the multiple comparisons fallacy.

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. 

Example #2:

In looking at the difference between 100 Christians and 100 atheists, we found that Christians were significantly more likely to eat tuna fish.

Explanation: When you fish for data, you are bound to catch something -- in this case, tuna.  Notice that because we were looking for anything, we are bound to find it.

Exception: At times, truth is revealed in data whether we look for it or not, but we need to realize that meaningless statistical anomalies are to be expected when looking at data.


This a logical fallacy frequently used on the Internet. No academic sources could be found.

Registered User Comments

Become a Logical Fallacy Master. Choose Your Poison.

Logically Fallacious is one of the most comprehensive collections of logical fallacies with all original examples and easy to understand descriptions; perfect for educators, debaters, or anyone who wants to improve his or her reasoning skills.

Get the book, Logically Fallacious by Bo Bennett, PhD by selecting one of the following options:

Not Much of a Reader? No Problem!

Enroll in the Mastering Logical Fallacies Online Course. Over 10 hours of video and interactive learning. Go beyond the book!

Enroll in the Fallacy-A-Day Passive Course. Sit back and learn fallacies the easy way—in just a few minutes per day, via e-mail delivery.

Have a podcast or know someone who does? Putting on a conference? Dr. Bennett is available for interviews and public speaking events. Contact him directly here.

About Archieboy Holdings, LLC. Privacy Policy Other Books Written by Bo
 Website Software Copyright 2019, Archieboy Holdings, LLC.