Understanding Genealogy Sources

As genealogists and family historians, we talk a lot about using sources. But I think that "source" is one of those words that of gets thrown around and we don't stop and think about what it really means. Let's take a look at understanding genealogy sources.

Understanding Genealogy Sources


What Is a Source in Genealogy?

What is a source? Is it a birth record? Is it a published book? Is it what your grandmother told you? Is it a database? 

A source could be any of those things. When it comes down to it, a source is whatever you use to get information. 

If you use a birth record to get information, that birth record is the source. If you use a tombstone to get a death date, that tombstone is a source. If you use a published book of marriage abstracts, that book is the source. If Aunt Bertha tells you something at the family reunion and you use that information, Aunt Bertha is your source. 

Yes, that means that if you use an online family tree for information, that online family tree is the source.

Two Basic Types of Sources

There are two types of sources for our genealogy research: original sources and derivative sources. (Some fields refer to sources as primary or secondary. However, genealogy classifies them as original and derivative.)

An original source is the first recording of that record. It has nothing to do with the information on the source. It has to do with the source itself.

That birth record that's recorded at the probate court, the family Bible that somebody wrote in, or the letter that your grandfather wrote to your grandmother during the war. Those are the first recording of that record.

That might make a bit more sense when we consider the second type of source: derivative sources. A derivative source is something that's either made from original sources or from other derivatives. It's derived from something else.

Let's say that the county probate court has marriage records. Those marriage records are the originals. If the local genealogy society comes in and makes a book of abstracts of those marriage records, that book that the society publishes is a derivative source. It was derived from, in this case, original records.

What Does This Mean for Our Research?

This is all well and good, but what does it actually mean for our research? If derivative sources are created from other sources (either original or other derivatives), consider what that means: it's changing formats. 

Every time that something changes format, it's another chance that an error can creep in. For that book of marriage abstracts that the genealogy society published, did they include all of the marriages? Did they copy the information correctly? Did they leave out some information? Did they make a typo when they were compiling their book?

This isn't to say that derivative sources are bad. They can actually be quite useful in our research. It is to say that we shouldn't stop with them. Those derivative sources came from somewhere else. There is something else to look at. Where did it come from? Working your way back to the original can yield additional information.

Are you trying to make sense of sources, evaluate evidence, and find more information? Check out my "Generations Cafe Circle" is designed to help you navigate your genealogy research with confidence and enjoyment. Click here for more information.

Understanding Genealogy Sources
Posted: April 27, 2018.

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  • I appreciate this post! It’s very informative and now I understand why there are multiple indexes for the same marriages!

  • My problem is with people. I am the researcher in my family and I received a lot of oral information from my parents. If my dad said that he was born in a certain hospital, his mother was married or died on this date, is my dad a primary source or a derivative source?

    • His words to you (the source) is original. However, the information would be secondary, as he wasn’t an eyewitness. (Unless he was there when his mother died; then that would be primary information.) The source is just the format — it isn’t the information. (We’ll talk about that next week!)

  • I have recently been taking that next step and seeking out the original documents even though the derivative gave me the dates or places I wanted to know and it’s like a treasure hunt!! I am not sure what took me so long! A great example is my five times great grandfather. He came over as a french soldier in Rochambeau’s French army in the Revolutionary War. He was discharged in the US and married my five times great grandmother. His name was Antoine but all the records I was finding used Anthony as his recorded name. A compiled book of marriage records had their marriage date and bond date. I have had that piece for years. Just a few months ago I got a wild hair and decided to order a copy of the originals from the state archives. Weeks later I received the envelope in the mail not expecting to learn much but happy to have it. When I pulled the paper out of the envelope what I saw was probably one of the more exciting moments in my genealogical experience…..he had actually signed the bond himself! And he signed as Antoine! Others were probably changing it on land records and what have you. It was the first moment that nothing was between Antoine and me ( except a few hundred years of course) it is the only record I have found on him that was in the first person. All along I have felt like everyone else was talking about him but across the years he let the world know he was Antoine. Since then I have been going back and seeking out the originals. Each one is a treasure and I learn a little more than just dates and places. I highly recommend going after the original source records!!

  • One of my most recent (date wise) brick walls was smashed when a cousin found the actual records. Bride’s maiden name was inadvertently published as husband’s name. Once we knew her true maiden name, it all made sense and we were able to go several generations further. If a source seems questionable, check it out!

    • Not sure what you are referring to as ‘authored’, but I recently got all excited when Ancestry sent me a notice that my great-great grandfather had been found!! I had looked for him for over 50 years of research! I checked the info but none of it could be documented and it was all wrong. They put my known great-grandfather’s information under this ‘found’ great-grandfather. I notified Ancestry and the ‘author’ hoping they could give me documentation, and to point out the error, but nothing has changed! Wrong information is floating around ‘out there’. The only way I use ‘authored’ is if I can follow it up with actual documents. It was a big let down for what had promised to be a big break through.

  • Sorry but a book is not a source. It might have a birth date but it is not the originator of the fact. The source of a birth is the institution originating the birth certificate. The book might be a citation describing the location of the source.

    • A source is wherever you get information from. Sources can be described as original or derivative. (Books would be considered derivative.) Ideally, we’re working with original sources, but derivative sources are still sources if that is where we’re getting our information.