Centurial: A refreshing source-first approach to genealogy

Centurial describes itself as “evidence-based” genealogy software, in contrast to the more common and standard “conclusion-based” software1. A common pushback I have heard against this description is that all genealogy should be evidence-based — after all, we should be following the Genealogical Proof Standard2, the foundation of which is finding the relevant evidence and ensuring our conclusions are based on it.

The key point that people miss is that Centurial’s self-described “evidence-based” nature isn’t about the genealogical process or your research methodology at all, but rather about the software itself.

Conclusion-based genealogy software

Let’s start by reviewing how most genealogy software works: you enter your conclusions, and possibly, if you’re diligent, add source citations to those conclusions. And that’s basically it! Under the hood, the software generally stores your tree data as a simple series of facts, which are then compiled into people, places, events, and relationships.

It’s true that it is possible to cite every source for every fact, but the software tends to have no opinions in that regard. And even if you do cite all your sources, it can be very difficult to tell where the specific value for a fact came from.

Consider this scenario: you go to someone’s tree (or your own!) and you see a birthdate attached to someone you’re researching. It has a ton of sources attached to it, which is fantastic! But as a diligent researcher, you decide you want to dig in and verify that the sources actually support the conclusion on display… only to find several things:

  • First of all, most of the sources say nothing about the birthdate of the target person!
  • And most concerningly, none of the sources actually list the specific birthdate conclusion that’s been reached.

Congratulations! You just wasted your time looking through all those sources. On the one hand, you avoided regurgitating a potentially erroneous conclusion, but on the other hand, maybe it’s right, but you have no (easy) way to know. But what happened? How did we even get here?

There are two main limitations of sources in conclusion-based genealogy software:

  1. You can generally only source full facts. This means that the source is being applied to the entire “birth” event, which encapsulates birth date as well as location, and is probably the reason that so many sources didn’t mention the birthdate at all: they were actually only relevant to the birth location, instead.

  2. A fact can only have a single value. Sure, you can have “alternate facts”, but I haven’t found that most software supports those very well, and even then, if you end up reconciling any discrepancies, you still only end up with a single value and a potentially confusing source situation. Another way to phrase this limitation is that there is no support for true value provenance: you can’t tell what specific values a source contains without going back directly to each and every source.

That’s one reason that so many professional genealogists advocate for keeping detailed research logs: because without it, you can easily hamstring yourself and get lost in a sea of confusing sources and inadvertently introduced errors. But do most hobbyist genealogists do that? Judging from the general state of trees on Ancestry, probably not.

And honestly, fair enough. I’m guilty of it, too. It’s hard to diligently follow a research process that the software only partially supports, and as an afterthought at that.

Evidence-based genealogy software

That is why I describe Centurial as “a breath of fresh air” — because unlike traditional genealogy software, Centurial truly supports a rigorous genealogical research methodology. But let’s skip back a bit. How exactly is Centurial different?

Honestly, on the surface, Centurial seems drastically different than other genealogy software, but once you get the hang of it, it’s very fluid to use. And, there’s a simple way of thinking about it that I think makes the whole thing make a lot more sense, so bear with me — I’ll get there.

While most genealogy software deals with facts first, Centurial deals primarily with sources. So the first thing we do in Centurial is to add a source — that’s an important point! There is no such thing as an unsourced fact in Centurial. It’s not possible.

The general process that you need to follow with Centurial is as follows:

  1. Add a source. Centurial makes it pretty easy with a little wizard to add well structured source citations following the Evidence Explained format3, which is the standard for genealogical research. There’s a bit of a learning curve, but even if you make mistakes, you can easily improve your citations later, so don’t worry too much about it.
  2. Enter any claims that the source makes. This is the key that makes Centurial different — we can never modify our tree directly. Instead, we can only enter what each individual source claims. For example, a birth certificate probably makes claims about the person’s name, birthdate, parents, and possibly other things. All of those are entered here and associated with the source.
  3. Correlate the source to the tree. At this point, the source is just a set of claims, but before we can have a tree, we have to “correlate” those claims. This is essentially the process of saying that “John Smith” in our source is the same as the “John Smith” from other sources. This is probably the biggest stumbling block for new users of Centurial — after we add the source and enter those claims, we just have a source that makes claims and have no idea how it relates to the rest of the tree! Centurial usually does a decent job of automatically correlating sources to the tree, but it will get tripped up, for example, if key details like names are different, so some user intervention might be required.

After that, it’s basically just rinse and repeat. Yes, there are some additional steps, such as evaluating the evidence for different conclusions, but those three steps cover the core of Centurial that makes it so different.

But now let’s go back to what I mentioned before: a simple way to think about Centurial that might make it a lot easier to understand.

With most genealogy software, you are making a single tree and attaching sources to individual bits and pieces of that tree. Centurial flips that on its head, so you are essentially making one mini tree for each source, and then telling it how those many little trees fit together to form one big tree. At the individual source level, entering tree data is very similar to traditional genealogy software: you’re just entering people, relationships, facts, and events. The difference is that all of those things are constrained to a single source.

That’s where the magic happens: since we now know all of the claims, in detail, that each individual source is making, we get value-level provenance without any additional effort! And Centurial does a pretty good job at inferring many others. For example, based on the birthdate of a child, it can infer, to some degree, the birthdate of the mother. Take this entry from my tree:

On average women have children between the ages of 15 and 50, this is indirect evidence for the birthdate to lie between March 10, 1902 and March 10, 1937)

This can be really powerful when you add many of those inferred claims together, which it is generally good at.

And the kicker is that Centurial tells us the source of each and every one of the claims that led to every possible conclusion — and we’re able to evaluate each on a claim-by-claim basis. It’s hard to express just how powerful that is.

Another benefit of all claims belonging to a source is that it makes experimenting with our research much safer. If you’ve ever had a hypothesis about parentage, or thought that a set of records belonged to one person, only to find out later that it didn’t, you probably know the pain of having to undo those changes later. Best case scenario, it’s just difficult, because you have to go and make changes one-by-one. Worst case scenario, though, and you might have to go through all of the sources and rebuild a chunk of your tree from the ground up.

With Centurial, however, it’s about two clicks to undo changes like that: we can simply uncorrelate or delete the sources. And BAM, done. It seriously feels like magic.


This post is getting long, so I’m going to wrap it up there. Centurial is fantastic and has encouraged and supported me in becoming a better family history researcher. The source-first approach that Centurial uses feels like magic and is hugely refreshing in a landscape of otherwise very samey genealogy software.

With that said, it does have its problems. Personally, I think the rigor and confidence it adds to recording our research definitively outweighs those problems, but they are there. In subsequent posts, I’m going to discuss some major limitations of Centurial, and how the developer could fix them.

For now, happy researching!



  1. Fouke Boss, Centurial (http://www.centurial.net/en/ : accessed 31 August 2023), “Home”.

  2. Board for Certification of Genealogists (https://bcgcertification.org/ethics-standards/ : accessed 31 August 2023), “Ethics and Standards”.

  3. Elizabeth Shown Mills, Evidence Explained (https://www.evidenceexplained.com : access 31 August 2023).