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Laura A. Murphy DeGrazia, CG, FGBS, “Skillbuilding: Proof Arguments,” OnBoard 15 (January 2009): 1–3.

Just as mathematicians construct proofs to convince others of the truth of mathematical statements, genealogists assemble proof arguments to convince others of their genealogical conclusions. A proof argument is a detailed, written explanation of the evidence and reasoning used to reach a genealogical conclusion.

Terminology: Proof argument, proof summary

The BCG Genealogical Standards Manual describes two styles of proof summaries.1 The most effective of the two styles takes a narrative form and is best called a proof argument. Proof arguments are useful in both simple and complex cases, but their detail and careful explanation is essential when thorny problems are resolved through analysis and correlation of complicated evidence (e.g., evidence that is indirect or conflicting). Even when a conclusion is comparatively straight-forward, genealogists would do well to support it with a proof argument.

The second type of proof summary, the cover-sheet list, is truly a summary. The usefulness of this abbreviated style is limited; its principal use occurs when we submit a collection of documents to a client and need to provide a summary list of those attachments.

Why write proof arguments?

The final step of the Genealogical Proof Standard requires that “we arrive at a soundly reasoned, coherently written conclusion.”Writing a proof argument satisfies that requirement. Proof arguments are frequently composed with the goal of publishing and disseminating information to invite challenge to a conclusion. Arguments defending our conclusions are also useful for our personal files or for clients. Very often the process of writing a proof argument will reveal to us weaknesses in evidence and logic where additional research is required.

Developing a proof argument

When reasonably exhaustive research, careful analysis, and correlation of evidence lead to a sound genealogical conclusion, a proof argument should be constructed to defend it. Standards 1 through 34 in the Standards Manual address data collection and evidence evaluation. All genealogical compilations must meet Standards 35 and 36. The format and content of proof arguments are addressed in Standards 44 through 49.3 Those who have never written proof arguments might use the following three steps:

  • Clearly state the problem or the question to be answered. Ask yourself a series of questions: Who is the subject of the argument? What particular question surrounding that person or family will the argument address? What is the hypothesis, the proposed solution? Be sure to include essential background information, such as inaccuracies in previously published information or limitations of available records.
  • Choose those pieces of evidence that best support your hypothesis. Make sure the proof argument includes all the evidence upon which the conclusion is based. (However, every piece of evidence uncovered during the course of research need not be mentioned.) Be selective. Include the best quality evidence available. (For example, opt for original versus derivative records.) Take care to cull extraneous evidence and unrelated information because these will detract from the focus. Do not omit contradictory evidence. When it exists, it must be presented and discussed.
  • Carefully plan the order in which to present the evidence. Effective proof arguments usually do not reveal the evidence in the order it was collected. Instead, the evidence is presented in a logical sequence that enables the reader to follow the line of reasoning. Make your discussion comprehensive yet clear. If contradictory evidence exists, explain why you reached your conclusion despite that evidence. Remember that all sources must be fully and accurately cited.

Certification Portfolio Requirements

Applicants for certification are required to submit at least three examples of proof arguments in their portfolio:4

1. The Case Study (requirement six) asks applicants to supply a “case study (or proof summary)…that (a) demonstrates application of the Genealogical Proof Standard, and (b) resolves, in your opinion, a problem of relationship or identity that cannot be resolved from uncontested direct evidence.”

2-3. The Kinship-Determination Project (requirement seven) calls for “proof summaries for at least two parent-child relationships in different generations.” Judges will evaluate the extent of research and the quality of sources used in each argument. They will also assess one’s ability to analyze and correlate evidence from multiple sources of varying reliability, to resolve conflicts (if any exist), and to justify conclusions clearly and convincingly.

Note: The kinship-determination project is a narrative in which you are to “explain linkages.” In a genealogical narrative, documentation is provided in footnotes or endnotes, not by a stack of documents that need a cover sheet. Therefore, if you choose to follow a “proof summary” model from the Standards Manual, you should not choose the “cover sheet list” format. Regardless of the type of evidence you use—direct, indirect, or contradictory—the appropriate choice is Appendix D’s “Source-Cited Text Format.”

Where and how should you weave the required proof arguments into the kinship-determination project? Insert the discussion at the point at which the kinship is asserted. The specific content and length of each proof argument will vary depending on such factors as the complexity of the evidence and information in the surrounding text. However, every proof argument must clearly identify the subject, focus and conclusion, and it must discuss both supporting and contradictory evidence (if any) to adequately defend the conclusion.

Learning more

Proof arguments form the basis for many articles published in scholarly genealogical journals such as The American Genealogist, the National Genealogical Society Quarterly, and the New England Historical and Genealogical Register. Other examples are available on the BCG website5 and in example 2 of Appendix D in the Standards Manual.6

For further guidance in developing proof arguments, you might


Proof arguments are essential when genealogical problems are solved by extensive research and analysis of complex evidence. They are valuable in simpler cases as well.

Writing them is a skill all genealogists will want to develop, regardless of whether they publish their work, document research for their own files, explain conclusions to clients, or seek certification through BCG.


1 The BCG Genealogical Standards Manual (Orem, UT: Ancestry, 2000), 16, 51–64. The Standards Manual refers to proof arguments as “source-cited text.”

2 Ibid., 1–2.

3 Ibid., 2–17.

4 The BCG Application Guide (Washington, DC: Board for Certification of Genealogists, 2007), 7, 8.

5 “Sample Work Products,” (http://www.bcgcertification.org/skillbuilders/worksamples.html: accessed 17 November 2008). See especially the links to Case Studies and Proof Arguments.

6 The BCG Genealogical Standards Manual, 55–64.

7 Elizabeth Shown Mills, CG, CGL, FASG, “Proof Arguments and Case Studies,” in Professional Genealogy: A Manual for Researchers Writers, Editors, Lecturers and Librarians, ed. by Elizabeth Shown Mills, CG, CGL, FASG (Baltimore: GPC, 2001), 389–408.


Laura A. DeGrazia, CG

This article was originally published in OnBoard, BCG’s educational newsletter and is protected by copyright. Individuals may download and print copies for their personal study. Educators are granted permission to provide copies to their students as long as BCG, OnBoard, and the appropriate author are credited as the source of the material. Republication elsewhere is not permitted.