FILE SELECTED // FILE 00
Natural Experiments
“Sometimes a rule, border, or event assigns exposure without researchers controlling the allocation.”
01 / SUMMARY
In short
A natural experiment uses external variation that creates exposed and unexposed groups. It can strengthen causal inference when allocation is credible, but remains vulnerable to bias and concurrent changes.
03 / SCENE
In the wild
A policy begins in one region before another, creating a time comparison the research team did not design.
04 / LIMIT
The limit
A natural event does not make assignment random or guarantee comparable groups.
FINAL NOTE
What remains
Investigate why units were exposed and what else changed at the same time.