Genealogical Proof Standard

“I just found out that I’m descended from King Edward V of England!” your friend tells you excitedly.

“Really?” you ask. “What proof do you have?”

Proof in Genealogy

How do we prove a relationship when it comes to genealogy and family history research? Just how much information and evidence do we need?

The answer is, it depends.

You might only need one original record containing primary information from a trustworthy informant which provides direct evidence for your research question.

Or, it could take many derivative records containing secondary or indeterminable information.

Basic Terms to Know

When doing any work in genealogy, it’s important to know and understand the differences between sources, records, information, and evidence.

Let’s take a look at each one of these in more detail.


The word source is often confused with ‘record’ in genealogy. Put simply, a source is a collection/container of records.

Some examples of a source are church registers, databases, authored genealogies, land deed books, vital record indexes and censuses.

A source should also not be confused with a repository. A repository is a physical location where sources are held (for example the New Jersey State Archives).

There are three types of sources:

  • Original: the original form of the record created at the actual time of the event.
  • Derivative: the copied, aggregated, or derivative version of original records. Derivative sources are usually created well after the actual event. For example, an index of vital records. Note that a ‘copy’ does not refer to a photocopy of an original record.
  • Authored works: the published research already conducted on the person/family/area of interest.

As responsible genealogists, we of course want to seek out original sources when possible.

Derivative sources and authored works are fantastic finding aids to locate original records.


Records are the individual page, line item, certificate, etc. within a source that documents an event or action.

Think of a death certificate. The source would be the actual collection of death certificates held at the particular repository, whereas the record would be the actual certificate of the person of interest.

Looking at the death certificate, there is a lot of information from various informants.


The information provided in our example death certificate is what’s actually written on the paper – not what may be inferred or what our opinions are.

Of course, not all information is the same. There are actually three distinct types of information:

  • Primary: information/facts given by someone who was actually at the event. For example, the cause of death given by the medical examiner would be primary information.
  • Secondary: information given by someone who was NOT physically at the event. For example, the birth date of the deceased given by a spouse. Their spouse was not physically at the birth.
  • Indeterminable: information given where you cannot determine the informant or how the informant knows the information given.

Remember that the classification of information does not refer to the record as a whole, rather the individual pieces of information written on the record (death date, birth date, parents names, the cause of death, burial information, etc.)

Now that we have an idea of the different types of information found in records, let’s look at how to evaluate the information by the evidence it provides.


Evidence is our interpretation of the information contained in a record. There are three types of evidence:

  • Direct: evidence that directly answers our question. For example, the cause of death listed on a death certificate.
  • Indirect: evidence that suggests an answer to our question, but does not directly answer it. More than one piece of indirect evidence will be needed to answer our question.
  • Negative: evidence that does not exist where we assumed it would. This leads us to make assumptions about the missing information. For example, you might infer that a child missing from a census record of his/her family has died prior to the census year.

Evidence is ultimately what we are after to solve or prove our research question.

The Genealogical Proof Standard

Now that you have a better understanding of some basic terms, let’s dive into the GPS.

Just how much evidence do you have to have? And how should it be organized?

The Genealogical Proof Standard, or GPS, was created to answer exactly those questions.

Because every case is unique, we can’t establish a specific number and say, “You must have five indirect pieces of evidence.” In some cases, five isn’t enough. In others, it may only take two.

Instead, the GPS is a process that helps you decide if you have enough evidence, then guides you through organizing and presenting it.

The GPS has five elements:

  • Reasonably exhaustive research
  • Complete and accurate citation of sources
  • Correlation and analysis of the evidence
  • Resolution of contradictory evidence
  • A conclusion that is soundly reasoned and written coherently

Reasonably Exhaustive Research

Many of us find research exhausting at times. But that doesn’t mean we’ve done exhaustive research.

When it comes to GPS, it means that you have considered as many sources of information as is reasonably possible. You didn’t stop with just two or three bits of information and say good enough, you kept digging.

There are dozens of possible sources to be located. Some are original sources with primary information that offer direct evidence, and if you do manage to find them, wonderful.

But if all you find are bits of indirect evidence, you need to look for every source you can get your hands on: probate and court records, census listings, newspaper articles, church records, local histories, etc.

Each one adds a piece to the puzzle.

Complete and Accurate Citation of Sources

When you do locate a source, record where you found it as completely and accurately as possible.

This not only lets other researchers verify your information, but it makes it far easier for you to find the source again if you need to take another look.

Don’t wait to document your sources. Write them down as you find them, and keep track of them in a single, centralized location.

A proper source citation generally includes the name of the author, title of the source, a catalog or other identification number, publication date, page number, and date you accessed the source.

Also, be sure to write down in which library, courthouse, archive, or other location you found it.

And above all, ALWAYS make a copy of the title and/or section pages if your source has one.

What may seem at first to be an original source of Church marriage records might actually be a handwritten copy done years after the original which would make that source a derivative and thus less credible.

Correlation and Analysis of the Evidence

Just gathering evidence isn’t enough.

You have to decide if they are reliable and useful, and then you must put them together to build a case.

Not every source is reliable/credible.

Just because you found it online or someone else said it was so, does not make it true.

That’s called hearsay.

More often than not, user-created family trees on sites like Ancestry are litered with incorrect names, relationships, dates and any number of other facts.

Don’t just copy what you see in someone else’s tree unless they have a documented trail of evidence.

If you have five different pieces of information that imply five different years of birth for the person you’re researching, obviously at least four of them are wrong.

Careful analysis of each piece of information and source is required to decide which is most likely to be accurate.

Correlating sources means taking information from two or more sources and combining them to generate new knowledge.

For example, say you don’t have a birth certificate for Michael Fleming, but you do for his brother Stephen.

In another source, Stephen states that Michael is exactly three years and seventeen days younger than him.

By correlating these two sources, you have some good indirect evidence to possibly prove Michael’s date of birth.

Just remember you still need to perform reasonably exhaustive research and that the more indirect evidence you use, the more evidence is required to reach your conclusion.

Resolution of Contradictory Evidence

What happens when you have sources and information that contradict one another? When using the Genealogical Proof Standard, you can’t just ignore one and pick the other willy-nilly.

Careful analysis is required. All conflicts must be resolved before you can prove your case.

A large part of resolving a conflict is determining how or why a particular piece of information is wrong.

Often this means digging up additional information. But once you can demonstrate that the contradictory information is not correct, you have resolved the conflict.

Contradictions can be annoying. They force us to dig deeper and reason more carefully. But that is exactly what we should be doing anyway.

If you cannot explain away the contradictory evidence, it may be impossible to build a convincing proof.

Conclusion Soundly Reasoned and Written Coherently

For some genealogists, this is the hardest step. But it is also one of the most important and useful things that we can do.

When building a proof using GPS, you link together all of the evidence that you found. You build a case that is sound and logical that leaves no conflict unresolved.

Then you put it in writing.

One of the greatest benefits of this step is that it forces you to identify and admit what assumptions you have made, and what contradictory evidence you have explained away.

And as you write, new ideas and new connections are likely to pop up that will benefit other areas of your family search.

If you can’t write a coherent, soundly reasoned conclusion, chances are you still have more research to do first.

If that’s the case, repeat step one of the GPS.

Who Should Use the GPS?

The short answer is everyone.

Professional genealogists rely on the Genealogical Proof Standard to ensure the work they do for their clients is of the highest quality.

Anyone submitting a case study to a genealogical journal or magazine is certainly going to be expected to follow the GPS.

But the more you use it in your everyday research, the better off you are going to be.

Don’t wait until you’re ready to start preparing a written genealogy or family history. Use the GPS every step of the way.

It will help guide your research and ensure you haven’t missed anything. It will make you more confident and secure in your conclusions, and keep you from constantly having to backtrack to verify information.

Disproving Is Easy, Proving Is Hard

In many cases, disproving something is much simpler than proving it.

Is your friend actually descended from King Edward V?

Not likely.

Ten seconds on Google will tell you that Edward V was never married and died when he was 12.

Proving facts and connections when you don’t have direct evidence is tough, but the Genealogical Proof Standard is there to help you and guide you through the process.

Additional Reading

This guide was written to give you some baseline knowledge of the GPS and how important it is to use in your research.

To learn more, I encourage you to pick up a copy of Genealogy Standards written by the Board for Certification of Genealogists.

I also highly recommend reading Mastering Genealogical Proof by Thomas Jones.

Leave a Comment