Triangulated Historical Research
Combine archives, interviews, and cross-checks into one reliable narrative
- Difficulty
- Advanced
- Time to result
- ~months to results
- Steps
- 6
- Confidence
- 97%
This method reconstructs complex history by triangulating three evidence layers: previously published work, interviews with participants and witnesses, and contemporaneous archival records. The researcher first maps what is already known, then uses primary and secondary interviews to expose missing details and disagreements. Newspapers, trade publications, correspondence, and other records provide an independent check on memories that may have faded or changed. Contradictions are resolved by comparing person A’s account with person B’s account and the record produced at the time. The output is not a collection of disconnected facts but a holistic narrative whose important claims have survived multiple forms of verification.
Origin
Robin Wigglesworth described using this method to research Trillions, his history of index funds, during an interview on Masters in Business.
Core principles
- 01Synthesize rather than merely summarize sources
- 02Combine documentary evidence with firsthand accounts
- 03Use secondary witnesses to fill factual gaps
- 04Cross-check recollections against contemporaneous records
- 05Treat retrospective claims cautiously when success creates competing origin stories
How to run it
- 1
Map the Published Record
Collect books, biographies, features, and prior histories covering any part of the subject. Note established facts, open questions, and disagreements.
Pro tip Use prior work as a foundation and source map rather than treating it as the final account.
Watch out Do not inherit another author’s interpretation without independent verification.
- 2
Interview Primary Participants
Speak with people directly involved in the events and ask them to reconstruct decisions, chronology, and motivations.
Pro tip Demonstrate preparation so busy sources know their time will not be wasted.
Watch out Participants may unintentionally misremember events or overstate their role.
- 3
Fill Gaps Through Secondary Sources
Interview colleagues, observers, successors, and other witnesses who can clarify missing details or provide alternative perspectives.
Pro tip Ask each source who else saw the event from a different position.
Watch out Do not treat proximity to a participant as proof of accuracy.
- 4
Search Contemporary Archives
Review reporting and records created when the events occurred. Use them to establish dates, public positions, and the context participants faced.
Pro tip Prioritize trade publications and specialist archives closest to the subject.
Watch out Contemporary reporting can also contain errors and should not stand alone.
- 5
Cross-Check Competing Accounts
Compare each important recollection with other interviews and contemporaneous evidence. Mark claims as established, plausible, disputed, or unsupported.
Pro tip Pay special attention to stories that make the speaker look unusually prescient.
Watch out Successful inventions often attract retrospective claims of authorship.
- 6
Build the Holistic Narrative
Integrate the verified evidence into a chronological explanation that connects people, incentives, decisions, and consequences.
Pro tip Preserve uncertainty where the evidence does not support a definitive conclusion.
Watch out Narrative coherence must not be achieved by concealing genuine contradictions.
In the wild
Wigglesworth combined books by Jack Bogle and other financial historians with hundreds of interviews and archival searches across Institutional Investor, Pensions & Investments, and The Wall Street Journal. He then compared participants’ retrospective accounts with one another and with reporting from the period.
→ The research produced a unified history while challenging simplified origin stories created after indexing became successful.
A journalist researching who created a financial product gathers corporate histories, interviews the original development team and external partners, and checks their claims against patent filings, launch coverage, meeting minutes, and dated presentations.
→ The final account distinguishes documented contributions from later reputation-building claims.
Common mistakes
Trusting the Most Famous Participant
Prominent participants may receive disproportionate credit or present a cleaner story than the evidence supports. Test their account as rigorously as every other source.
Collecting Without Synthesizing
A large archive is not automatically a useful history. The researcher must connect evidence into a clear account of causation and chronology.
Forcing Certainty
Some private decisions cannot be reconstructed conclusively. State the limits rather than selecting the most convenient version.
Is it for you?
Best for
It is best for journalists, authors, researchers, and analysts reconstructing events involving many participants and disputed memories.
Not ideal for
It is not ideal for quick commentary that cannot justify extensive interviews and archival work.
From the transcript
“what I try to do was essentially combine and synthesize all these disparate sources”
“just an exhaustive dive through the archives of institutional investor and pensions and investments in the Wall Street Journal and combine that into one holistic…”
“cross checking what person A said versus what person B said, and what the contemporary these newspapers might have said at the time.”
From the episode
Robin Wigglesworth on the Creation of the Index Fund (Podcast)
Robin Wigglesworth