A researcher finds a death certificate naming an ancestor’s parents and stops there, satisfied. The certificate is real, it’s specific, and it answers the question. It also happens to be secondary information, supplied decades after the fact by someone who wasn’t present at the birth — a point covered in an earlier article in this series. A marriage record for that same ancestor, sitting unchecked in the same courthouse, might name the parents too — and might not agree. The first element of the Genealogical Proof Standard exists precisely to catch this kind of premature stopping point: reasonably exhaustive research.^[1] The hard part has never been understanding that the standard exists. It’s knowing, in any given case, when it’s actually been met.

What “Reasonably Exhaustive” Doesn’t Mean

It doesn’t mean every record that could conceivably exist. It doesn’t require tracking down the one document that slid behind a filing cabinet at a courthouse forty years ago and was never seen again.^[2] Genealogy Standards defines the goal more precisely: genealogists attempt to collect all information potentially relevant to the specific questions they’re investigating.^[3] That last phrase carries the real weight. “Potentially relevant” is bounded by the question being asked — not by everything that has ever been written about a person.

The Research Question Sets the Scope

A vague goal like “learn about my ancestor” has no natural stopping point, because almost anything could be relevant to it. A specific question does: Who were Anna Dillmann’s parents? narrows the search to a specific, checkable set of record types — birth and baptismal records if they survive, her marriage record (which may name her parents), her death record and obituary, probate records for anyone who might have been her father, and land or court records that might mention her by a maiden name alongside a father or brother.^[4] Finding one record that answers the question isn’t the finish line. Reasonably exhaustive research means checking the other record types that could plausibly answer the same question too, specifically so a contradiction doesn’t surface later from a source that was simply never consulted.

Record Types Worth Checking — and Often Skipped

A handful of record types show up constantly in professional genealogical research and just as constantly get skipped by researchers working from vital records alone:

• Church records. Baptismal, marriage, and burial registers frequently predate civil registration by decades, and often record details — godparents, exact birthplaces, prior marriages — that civil records never captured.
• Tax lists. Annual tax records can place a specific person in a specific county for years with no vital record, and a name disappearing from a tax list is itself informative — a death, a move, or a transfer of property to an heir.
• Land and probate records. Deeds, wills, and estate inventories routinely name relationships — heirs, executors, witnesses — that no other record type documents, and they often survive for periods and places where vital records don’t exist at all.
• Newspaper notices. Marriage announcements, obituaries, and even routine local reporting (a visit from an out-of-town relative, a business notice) can supply a maiden name, a hometown, or a family connection found nowhere else.
• Court records. Guardianship filings, naturalization papers, and civil suits often surface family relationships as an incidental detail of an otherwise unrelated legal matter.

None of these are exotic. They’re simply less convenient than a vital record database with a name-search box, which is exactly why they get skipped — and exactly why they’re often where the missing piece of a research problem turns out to be.

Knowing What Existed

Reasonably exhaustive research also requires knowing what record types were even being kept in a given place and time, since the absence of an expected record type is meaningless if that record type never existed there to begin with.^[5] An American researcher accustomed to individual-level 1850-onward census schedules has to adjust expectations for an 1830 household-only census, or for the parish-register-based record-keeping of eighteenth-century German states, where civil birth registration didn’t exist yet at all. Reasonably exhaustive research in a Hessian village in 1780 and reasonably exhaustive research in Ohio in 1880 draw on almost entirely different record sets — and knowing which record types actually apply to a given time and place is itself part of the research, not a shortcut around it.

Genealogists attempt to collect all information potentially relevant to the questions they investigate — not all information that exists.

When to Stop

There’s no fixed number of sources that satisfies the standard. A more useful signal is whether continued searching in reasonably accessible sources is still changing the picture. If the timeline holds together, if the FAN club corroborates the conclusion from multiple independent angles, and if the record types known to exist for that time and place have actually been checked rather than assumed unavailable, a researcher has usually reached the point of diminishing returns. That point can arrive after five records or after fifty, depending entirely on how many independent record types survive for the specific person, place, and era in question. What matters isn’t the count. It’s whether the researcher can honestly say every reasonably available avenue was checked, not just the first one that gave a satisfying answer.

For Dillman Researchers

• Write down the specific question before searching, not just the ancestor’s name. “Where was Johann born” and “who were Johann’s parents” point toward different record types.
• Build a checklist of record types for the relevant time and place before starting, rather than searching opportunistically and stopping at the first hit.
• Treat the DFA’s incompletely documented family groups — such as Groups 46, 105, and 129 — as an invitation to look past the vital-record types already checked and into land, tax, church, and newspaper sources that may not have been searched yet.
• Don’t mistake “I found an answer” for “I found the answer.” The first satisfying record and the correct one are not always the same record.

Reasonably exhaustive research isn’t about collecting everything. It’s about being able to say, honestly, that the records a competent researcher would have checked were checked — and that the conclusion survived the checking.

Sources

1. Board for Certification of Genealogists, Genealogy Standards, 2nd ed. rev. (Nashville: Ancestry, 2021), summarized in “Genealogical Proof Standard,” FamilySearch Research Wiki (accessed July 2026).
2. Amy Johnson Crow, “How the Genealogical Proof Standard Can Help Your Research,” amyjohnsoncrow.com (accessed July 2026).
3. Judy Kellar Fox, CG, “Ten-Minute Methodology: What Is ‘Reasonably Exhaustive’ Research?” Board for Certification of Genealogists (accessed July 2026).
4. Kate Eakman, “Genealogical Evidence and Proof: How to Know If You’ve Compiled Enough Evidence,” Genealogy Gems (accessed July 2026).
5. Thomas W. Jones, Mastering Genealogical Proof (Arlington, Va.: National Genealogical Society, 2013), chap. 3, “GPS Element 1: Thorough Research.”

AI Disclosure: This article was researched and written with the assistance of Claude, an AI assistant developed by Anthropic. General claims about the Genealogical Proof Standard are drawn from the sources cited above; DFA-specific claims are drawn from the association’s own Family Group Sheet Database and prior published articles.

Notes

1. References to the DFA’s Family Group Sheets database, including Groups 46, 105, and 129, are drawn from the Dillman Family Association, Family Group Sheet Database, compiled 2026.