# Ecological fallacy

*Also called: Group to individual inference*

- **Cluster:** Part and whole — Traits smuggled between members and groups
- **Page:** https://fallacy.wiki/fallacy/ecological/
- **In Arabic:** https://fallacy.wiki/ar/fallacy/ecological.md
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/

## What it is

Drawing a conclusion about an individual from statistics about the group they belong to.

## In the wild

> That region is wealthy, so this resident is wealthy.

## How to answer it

Ask for individual-level data. Group averages do not describe members.

## Origin and naming

Named and pinned down in 1950 by the sociologist William S. Robinson, in a paper that showed correlations computed across groups can be far stronger than the same correlations across individuals — so reading them as the behaviour of individuals is a formal mistake. The name is a historian's artefact: Robinson was studying 'ecological' (region-level) data, not ecology.

## More places it shows up

- Employees in four-star-rated companies report more time for deep work, so Sani at a four-star company must be a deep worker.
- Neighbourhoods with more green space show lower stress levels, so Mrs. Itani, who lives across from the park, is not stressed.
- High-browsing cities produce more reading per person, so this visitor at the book fair is a reader.
- Users in industries with the lowest churn pay the highest rates, so this client joining from that industry will accept any price.

## How to spot it

- Notice when the only number on the table is a group figure and the conclusion lands on one named person.
- Notice averages doing the work that a membership list would do — average salary, average turnout, average score.
- Notice when 'the city', 'the region', 'our users' is spoken of as if it were one person.

## Nearby

- [Fallacy of division](https://fallacy.wiki/fallacy/division.md)
- [Fallacy of composition](https://fallacy.wiki/fallacy/composition.md)
- [Base rate neglect](https://fallacy.wiki/fallacy/base-rate.md)

## Read more

- [Wikipedia](https://en.wikipedia.org/wiki/Ecological_fallacy)
- [Simply Psychology](https://www.simplypsychology.org/ecological-fallacy.html)

---

From fallacy.wiki — a bilingual field guide to 91 logical fallacies, published by phi holdings. Licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/): reuse freely with attribution to fallacy.wiki.