The problem with averages

What it is

An average can hide wide spread, skew and outliers, so it may describe nobody in the group. A billionaire walking into a bar makes everyone in it a billionaire "on average".

Related

• Ecological fallacy fallacy
  The ecological fallacy and the problem with averages are both about taking a group-level figure as true of every member.
• Will Rogers phenomenon bias
  Both show how summary statistics can mislead: an average can hide the spread, and moving items between groups can raise both averages.

Appears in

• The 99 thinking errors in Rolf Dobelli's The Art of Thinking Clearly#55: The problem with averages

References

• Wikipedia: The problem with averages en.wikipedia.org
• The 99 thinking errors in Rolf Dobelli's The Art of Thinking Clearly en.wikipedia.org
• Wikipedia: List of cognitive biases en.wikipedia.org
• Wikipedia: Cognitive bias codex en.wikipedia.org

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