Lesson 11 min 20 XP
Source Triangulation
How to verify a claim by finding independent corroborating sources and understanding why multiple sources strengthen confidence.
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How to verify a claim by finding independent corroborating sources and understanding why multiple sources strengthen confidence.
Source triangulation is the practice of verifying a claim using at least three independent sources. The principle comes from navigation — if you can take bearings from three different points, you can pinpoint your exact position. In journalism and fact-checking, the same logic applies: if three unconnected sources independently confirm the same fact, the probability of it being wrong drops dramatically.
The key word is 'independent.' Three news articles that all cite the same original report are one source, not three. Three eyewitnesses who were standing together and have since discussed their accounts may have contaminated each other's memories. True triangulation requires sources that have no connection to each other and no reason to coordinate their accounts.
The strongest triangulation combines different types of evidence. A human source says an airstrike hit a hospital. Satellite imagery shows the damage. A medical organization confirms casualties. Social media video shows the aftermath. Each source type has different vulnerabilities — a witness might be mistaken, satellite imagery might be misinterpreted, an organization might have an agenda — but the chances of all four being wrong in the same direction are vanishingly small.
This is why Bellingcat's investigations are so credible: they combine social media analysis, satellite imagery, geolocation, and public records. Any single source could be challenged, but the convergence of multiple independent evidence streams creates near-certainty.
In your own information consumption, apply the same principle. Before sharing a dramatic claim, ask: can I find this confirmed by at least two other sources that did not get their information from each other? If the only source is a single social media post or a single news outlet, wait for corroboration.