Define the event
Specify actors, location, interval, type of change and decision. Avoid collecting everything matching a keyword.
GUIDE / PROTOCOL
Reconstruct a timeline of public signals
Order of appearance on a platform does not establish the order of events.
Direct answer
How do you build a verifiable timeline from open sources?
Define the change under study, then record claimed dates, observed dates and capture dates separately. Link every event to its source and uncertainty; look for earlier versions before inferring causation.
01 / Review method
Review method
Collect milestones
Record earliest found version, updates, announcements, repetitions and corrections. Note timezone and precision of each date.
Separate clocks
Distinguish alleged event, publication, indexing, viewing and archiving. A late capture does not date the event.
Test relationships
Compare sequences with other sources and competing hypotheses. Publish an annotated timeline, not an unsupported causal story.
02 / Evidence to keep
Evidence to keep
Milestone table
Event, date and time, timezone, date type, URL and verification status.
Retained versions
Copy or archive reference, capture timestamp and material differences.
Reuse chain
Who cites whom, repetition date and any correction to the first source.
Critical reading
Established events, uncertain intervals, alternative explanations and review point.
PRACTICAL CHECK
Before reaching a conclusion
A frequent misreading and the check that helps avoid it.
Premature conclusion
The date of a capture or share is not necessarily the date of the depicted event. Conflating them can reverse causality.
Decisive check
Record alleged event, earliest located publication, edits, reposts and access time separately, with time zone and confidence level.
AFTER THE REVIEW
Decide from the evidence
An archive appears after the alleged event
The archive at most establishes the page at capture time. Look for an earlier trace and leave the event undated if none exists.
A correction removes the original wording
Keep both versions, date each observation and explain which finding the correction changes.
OSINT / Official references
When dating a public signal
Event, filing, publication and capture dates mark different moments; record them separately.
BODACC
Why start hereDate publication of a French commercial notice.
Limit to rememberA notice records a published event; it does not describe the entity’s entire current activity.
Read source entryTED — Tenders Electronic Daily
Why start hereFollow published stages of a European procurement procedure.
Limit to rememberA notice does not prove contract delivery or outcome; read its stage and linked documents.
Read source entryWayback Machine
Why start hereLocate wording in an archived web-page version.
Limit to rememberCaptures can be partial; their date and content do not validate the page’s claims.
Read source entry03 / FAQ
Frequently asked questions
Does an archive prove creation date?
No. It shows a capture at one time, not necessarily the first publication.
What about approximate dates?
Keep the interval or stated precision instead of inventing an exact time.
Keep every repost?
Only those needed to understand spread or a changed message.
When revise the timeline?
When an earlier source or documented correction changes the sequence or interpretation.
04 / Official references