The Average Is
Hiding Something

 

An average can be accurate and still hide the most important part of the story.

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Community-wide statistics are useful because they give us a simple summary. But averages can also smooth over meaningful differences between groups. This experiment lets you start with a single headline number, then reveal how that same result varies by age.

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What this demonstrates
Segmentation • Survey analysis • Data visualization • Translating research into decisions

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Data: 2025 Greater Boston Jewish Community Study
Created by Daniel Parmer, PhD

 

About this experiment: The overall percentage does not change when the age groups are revealed. What changes is the level of analysis. Sometimes the average turns out to be a reasonable summary; other times it conceals large differences between groups. The point is not that averages are misleading—it is that good analysis asks what the average may be leaving out.

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