Verify a claim using open sources

実践チェックリスト

1. 01

   Define a testable claim

   Write precisely who allegedly did what, where and when. Separate the question from expectations to avoid looking only for confirmation. Separate an organisation from a namesake, subsidiary or account discussing it. Record the identifiers used and unresolved ambiguity. A conclusion should answer a question whose answer could change with new evidence.

2. 02

   Trace the earliest source

   Find the original document or media, its date and publication context. A screenshot or repost does not establish authenticity. Find the complete edition and earliest accessible publication, then check whether it cites an earlier origin. Preserve the context around an excerpt: titles, captions, dates and corrections can change its interpretation.

3. 03

   Document provenance

   Keep public URLs, access times and transformations. Preserve useful files while respecting rights, personal data and local law. Record what was collected, how and under which preservation permissions. A file hash can help detect changes but does not establish that the contents are true. Limit personal data to the defined purpose.

4. 04

   Find independent evidence

   Cross-check different source types: institutional publication, technical observation and primary document. Identify repetitions of the same dispatch or report. Build a small map of relationships between publications. Three sites citing the same release represent a distribution chain, not three observations. Seek confirmation that contributes distinct primary information.

5. 05

   Test alternative explanations

   Look for reused old imagery, timezone errors or missing context. Metadata may be missing or altered and is insufficient on its own. Test a competing explanation before concluding: an old company name, a place with the same name, a superseded document or an out-of-context photograph. Record important negative checks so readers understand the limitations.

6. 06

   Write a proportionate conclusion

   Separate facts, hypotheses and unknowns. Attribute statements, explain limitations and identify what could strengthen or refute the conclusion. An actionable brief separates observation, inference and open questions. It identifies the decision consequence, next verification and review date. Wording should remain proportionate to the evidence.

   Worked example: an image is claimed to be recent and from a named city. Look for an earlier publication, then compare visible geographic features and available timing evidence. If the location is plausible but the date cannot be verified, preserve those conclusions separately. Cite the evidence supporting each and do not turn plausibility into certainty.