The end goal of all genealogical investigations is to establish proof, by which we mean a convincing, credible case for a specific ancestral identity, relationship, or life event. By thorough research in sources, we must find sufficient detailed, matching evidence to uncover and reconstruct relationships and events relating to our research target, and only our research target.
But how do we decide when an accumulation of evidence reaches a threshold that we call proof? How do we define it? How do we decide when it has been met? How do we assess what others have proposed as proof? Is there just one valid definition of proof or are there many? These are questions that are central to the pursuit of genealogy.
Why is a definition of proof important for genealogy?
Once, in those not so distant pre-Internet days, many genealogists laboured away in near isolation, uncovering family histories from public, private or academic sources then sharing the outcomes within their families. Today, genealogy is a collective activity, nourished by easy online access to many sources, supported by vibrant societies and online communities. We share ideas and knowledge, we communicate with and educate one another, and, crucially, we often share our findings. One need only take a brief look at the thousands of published trees on Ancestry and other large subscription sites to understand the ubiquity of sharing amongst family historians. Some, such as the LDS Church, have even gone as far as to suggest that an end goal of collective sharing could be a single, comprehensive family tree of everyone.
But, as many who have looked at shared online trees in any detail, one quickly realises that the published conclusions of some family historians can stretch credulity. At best it can be said that there is a variable interpretation of what is required to establish a genealogical proof.
A standard definition of what constitutes proof is clearly necessary for any serious genealogical endeavour, as without a consistent measure of proof we can’t achieve consistent outcomes. When collaborating with others, it is an essential.
A History of Genealogical Proof
In the UK there has never been an official definition of genealogical proof – something which I have found troubling. In the USA however, the Board for Certification of Genealogists (BCG) has been a leader in setting out formal definitions and, where needed, updating them over time.
The BCG’s original definition of genealogical proof was based on the legal standard of proof as used in civil court cases. This principle is called the Preponderance of the Evidence, which amounts to “when I weigh all of the pros and all of the cons, I think that the pros outweigh the cons.”
Sounds reasonable, right? But there’s a catch – the margin by which the pros outweigh the cons can be tiny, even infinitesimally small. Where there is a significantly larger quantity and quality of evidence on one side this can work, but in marginal cases this can lead to conclusions which we might view today with some suspicion.
In the late 1990s, the BCG recognised the weaknesses of Preponderance of the Evidence and developed a new definition of called the Genealogical Proof Standard (GPS), which they published in 2000.
The Genealogical Proof Standard
The GPS is a five-step process which defines a well conducted genealogical investigation. It can be simply summarised as: search, cite, analyse, consolidate, and conclude. To have met the standard, the researcher must show that their whole investigation (not just the conclusions) meets all five of the elements.
1. Reasonably Exhaustive Search
Full text: “Reasonably exhaustive research – emphasizing original records providing participants’ information – for all evidence that might answer a genealogist’s question about an identity, relationship, event, or situation.”
So, what is a “reasonably exhaustive search“? Simply put, it is a search that has examined all potentially relevant sources. It implies that we start our investigation by finding out what the potentially relevant sources will be, list them and then search them all in turn, consulting the original or an image of the original wherever possible. By doing so we minimise the risk of undiscovered evidence emerging later to overturn an initial, perhaps hasty, conclusion.
2. Complete, Accurate Source Citations
Full text: “Complete, accurate citations to the source or sources of each information item contributing – directly, indirectly, or negatively – to answers about that identity, relationship, event or situation.“
Thorough, accurate citing of sources helps us to remember where we found the information we rely on as evidence and enables others to validate that our search has indeed been “reasonably exhaustive”. Assuring others of the quality of our search is doubly important, it enables them to:
- replicate our steps; and
- contribute their own ideas about other relevant sources which could enhance our research.
Citation is the single most effective tool for enabling effective collaboration between genealogists.
3. Analyse and Correlate Sources, Information and Evidence
Full text: “Tests – through processes of analysis and correlation – of all sources, information items, and evidence contributing to an answer to a genealogical question or problem.“
What this really means is that we need to make a sound interpretation of the evidence at our disposal. Kick the tyres, make sure that it stands up to scrutiny, be honest with ourselves about any gaps or deficiencies that may be there. This is the right point to consider whether the evidence we’ve collected forms a full and coherent picture. Is it the best available evidence? Is there any other potential evidence we could add to our search to strengthen our case? Is the evidence sufficient to support our conclusions? Will our conclusions reflect all the relevant evidence, good and bad, direct and indirect, positive and negative?
4. Resolve Conflicting Evidence
Full text: “Resolution of conflicts among evidence items pertaining to the proposed answer.“
It is a genealogical truism that any sufficiently exhaustive search will uncover at least some conflicting evidence. The corollary is also often true, that if you’ve failed to find any conflicting evidence then you may not have performed a sufficiently exhaustive search!
Analysing and resolving conflicting evidence is an essential step. Are we able to understand what the conflicts in the evidence might mean? Can we account for them? Or does the conflicting nature of the evidence put our conclusion into doubt? If we’re unable to resolve conflicting evidence satisfactorily then we will not be able to formulate a credible conclusion.
5. Soundly Reasoned, Coherently Written Conclusion
Full text: “A soundly reasoned, coherently written conclusion based on the strongest available evidence.“
At first glance, this element of the GPS seems like a non-sequitur. Conclusions must be:
- soundly reasoned – as no-one would accept a conclusion that relied on unsound reasoning;
- coherently written – as no-one would accept a conclusion that was written incoherently; and
- based on the strongest available evidence – as no-one would accept a conclusion based on partial, weak, or inaccurate evidence.
What this really means is that our conclusion must be based on a sound appreciation of what evidence was available, that we accurately interpreted and collated the evidence, and show how the evidence leads to the conclusion. It enables us to demonstrate that our conclusion is not only valid, but free from bias, preconception, or inadequate appreciation of the evidence.
What the GPS is – and what it isn’t!
There is little doubt that the Genealogical Proof Standard is a significant improvement upon Preponderance of the Evidence. It sets a far higher standard for proof to be achieved – no more dodgy marginal cases – and roots its requirements in the language of genealogy rather than a legal framework which has doubtful relevance to our pursuit. It is applicable to all genealogy work, not only in the USA but all around the world, whether professional or amateur. It sets clear expectations on how we should plan, execute, and document our work. It creates a common standard and supports common outcomes that can be scrutinised, replicated, or refuted. It is a vital tool that all genealogists who have mastered basic sources should try to understand and engage with. It is the missing link that may, in the future, allow genealogy to be the truly collective experience that it could and, many would argue, should be.
But it has problems too:
- it isn’t a single, cogent statement against which a documented conclusion can be measured;
- there is no straightforward checklist one can use to say “if these items are covered in the documented findings then it passes”;
- to assess whether a documented outcome has met the standard, the assessor must have access to details of how the investigation was conducted;
- the five steps of the GPS each have detailed definitions which require some knowledge and skill to understand fully and utilise.
One can easily use the GPS to assess formal genealogy reports, but it is simply not possible to use it to assess the principal form of communication in modern genealogy – the online tree.
So, if it has shortcomings should we be making efforts to use it? Yes! Yes! Yes!
The GPS is the only agreed standard for genealogical proof. It is the best available and we should all be using it so that:
- we have confidence in our own conclusions;
- we have confidence in the conclusions of our peers and collaborators; and
- we can share our work in the confidence that it can be used as the basis for further investigation without the need to be re-verified from top to toe.
It is a sad fact that in the laissez-faire world of shared online trees, one must re-assess all findings before using any element for one’s own purposes. Consciously using the GPS can reduce needless rework and, most importantly, make us all better genealogists.
The GPS is not perfect – even investigations that follow it thoroughly and accurately can’t ensure perfect certainty in their outcome. (We are engaged in family history, not mathematics, so there can never be perfect certainty!)
It is a little daunting, but it is the best framework and standard that the global genealogy community has. Once mastered, it can and will save you time, effort, energy, and tears!
Have I persuaded you that the GPS is the best way forward for your genealogy? Please let me know in the comments below.
- Board for Certification of Genealogists, Genealogy Standards (Board for Certification of Genealogists, 2nd Edition 2019).
Personal note: This is one of the single most important, yet least readable, books in the history of genealogy!
- Anderson, Robert Charles. 2019. Tools for Testing Genealogical Proofs. Talk delivered at RootsTech London, 24 October.
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