How many sources do you need?

Sources provide us with information about our families, events they participated in or which impacted on their lives, and the places that they lived or visited. The big question is, how many sources do we need to compile an accurate family history?

There are actually two parts to this question:

• how many sources should you use, and
• how many sources should you cite.

I am not sure what other researchers do, but I cite all or close to all of the sources that I use on the master version of my family tree which I keep on my computer. My online trees tend to have fewer citations.

One source is better than none

If you have read about the methodology of family history research or attended any lectures on the topic you will know that a family history without any source citations is virtually worthless.

A family history without source citations may be accurate and the creator may have used hundreds of sources. However, without citations only the creator of the family history will know that. Others will be reluctant to accept it or to use it, because each piece of information would have to be verified through further research. And, without citations the creator of the family history will find it more difficult to progress their research.

So, one source citation for each piece of information is better than none. It shows you and others where you got the information.

However, all sources can contain errors, gaps in information or deliberate alterations. So, relying on one source for each piece of information is unlikely to generate an accurate family history.

Two sources are better

If you use two sources for each piece of information, you can compare the information. If the information between the sources is consistent, then you and others can feel more confident that the information is correct and that your family history is accurate in that respect.

Confidence in the information from two sources will increase if:

• the sources were created independently of each other
• the sources are considered to be reliable
• there are no inconsistencies in other sources relevant to that individual.

Some would add to this list that at least one of the sources needs to be an original source. I do not disagree with the value of original sources, but I would include that under the dot point about using reliable sources.

More is best

Even two independent, consistent and reliable sources may not be sufficient.

The more sources that you have, the more likely you are to detect errors or inconsistencies. Having more sources increases confidence that your family history is accurate.

You need to use your own judgement, but I would suggest that you need more than two sources:

• if there are any errors, gaps or inconsistencies in the two sources even if they are not related to the information you extracted, because this suggests that the sources may not be as reliable as you would like
• if either or both of the sources were not contemporary with the event
• if the information was secondary information – that is, it was provided by an informant who did not have first-hand knowledge or first-hand experience of the event
• if the information provides indirect evidence, which requires inference to reach a conclusion
• if the identity of the people involved is in question – i.e. if you are unclear whether the person in the source(s) is the right person
• if getting that piece of your family history accurate is particularly important – for example, the name of a parent or where a name change is involved
• if other researchers disagree with your conclusions or have different information and their family history appears to be well researched.

For more of my articles about planning your family history, go to the Plan page.

For more of my articles about analysing sources, go to the Analyse page.

Post last updated 5 June 2024