Guide · Updated July 2026
The Genealogical Proof Standard (GPS) is the benchmark genealogists use to decide when a conclusion is proved. It has five elements, and all five must hold: reasonably exhaustive research, complete and accurate source citations, thorough analysis and correlation of the evidence, resolution of any conflicting evidence, and a soundly reasoned, coherently written conclusion. Note that “GPS” here means the proof standard — not geolocation.
The five elements
- Reasonably exhaustive research. You have searched the sources that could reasonably be expected to answer the question, including the ones that might contradict your theory. “Reasonably exhaustive” does not mean infinite; it means you did not stop at the first convenient record.
- Complete and accurate source citations. Every fact is cited so another researcher could find the same source and judge its reliability. This is where a citation style like Evidence Explained comes in.
- Thorough analysis and correlation. You weigh each source for the quality of its information and correlate it with the others, rather than treating every record as equally trustworthy.
- Resolution of conflicting evidence. Where sources disagree — two different birth years, say — you explain the conflict and why you accept one over the other, instead of ignoring the inconvenient one.
- A soundly reasoned, coherently written conclusion. You state the conclusion and the reasoning in writing, so the proof can be read and evaluated.
Why it matters
The GPS is what separates a documented conclusion from a guess. It is a standard for the reasoning, not a threshold number of sources: ten weak records do not prove anything, and a single strong record rarely does either. Certifying bodies and courts that accept genealogical evidence expect work to meet it.
The standard was defined by the Board for Certification of Genealogists and is set out in full in Genealogy Standards. It replaced the older, looser idea of a “preponderance of the evidence.”
How software helps you meet it
Each element maps to a concrete habit that a research tool can support:
- Exhaustive research — a research log and a repository/exhaustion checklist so you can see what you have searched and what you have not, including negative results.
- Complete citations — citation templates that produce a full first-reference note, a short form, and a source-list entry for each source.
- Analysis, conflict resolution and conclusion — an evidence workspace where you record each source’s quality, note conflicts, and write the conclusion.
In AncestorOS these are Pro-tier tools: Genealogical Proof Standard–aligned research logs, Evidence Explained citation templates (14 templates across 11 record categories, each producing all three citation forms), and an evidence-analysis workspace.
Frequently asked
Put it into practice
AncestorOS gives you Evidence Explained citation templates, Genealogical Proof Standard–aligned research logs, GEDCOM import and export, and DNA match tracking in one web-based workspace.
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