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What is the Leeds Method and How is it Used?

I had heard about the Leeds method and had some idea of what it entailed but to my shame I hadn’t really looked into it until very recently. You see my family tree is a little complicated and well essentially we do not know who my mother's father was although there was a theory.

Well recently thanks to DNA we were able to determine that our theory of who my maternal grandfather was, was in fact not correct. So back to the drawing board and cue the Leeds method. I will simply say it worked and it worked great.

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So in this post we are going to take a look at the Leeds method of correlating DNA matches. We will answer questions like where it came from, how it works and also most importantly how to do it correctly.

Who Invented the Leeds Method?

It was back in 2018 when genealogist Dana Leeds was trying to assist someone with understanding their DNA match results. They wanted to better understand their biological origins. Leeds had some training in Biology education so decided to help.

Dana Leeds created a method whereby you could visually group your DNA matches based on their likely connections to you. This became the Leeds Method and became an instant hit in genealogist circles.

What Is the Leeds Method?

The Leeds Method is essentially a clustering technique that uses colors to help you identify groups of DNA matches. These groups can then be associated ideally with the same common ancestors helping you better understand how you are related to them.

Obviously the main idea is to use the method to help organize your DNA matches list but there are some other benefits to the Leeds Method.

  • It may help identify unknown biological parents
  • Connect you with networks of DNA matches who can help you crack family tree brick walls
  • Help Identify distant unknown ancestors

How Does the Leeds Method Work?

This clustering technique works mainly with the use of a table and four colors which each pertain to a specific grandparent. I personally used an excel spreadsheet for my attempt and the Leeds Method but you draw your own table or create one in Word or for free with Google Sheets.

The basic idea is that you identify people who are DNA matches to you and who also share other DNA matches as well. This usually means that they, along with you, all share a common ancestor. Knowing that you share a common ancestor with 5 other people will usually indicate that they all come from one of the four lines created by your grandparents.

In my case, identifying three groups which must have been connected to three of my known grandparents helped me discover a small group who showed no connection to any of them. This must mean that they are connected to my unknown maternal grandfather.

How to Perform the Leeds Method

The first step in performing the Leeds method is to go to your DNA results and locate your list of matches. I did this with Ancestry because they give you the option to see shared matches. Locate the matches you have with whom you share between 90-400 centimorgans of DNA.

It is important to keep the range of matches you use for the Leeds Method between 90-400 in order to get an accurate result. Your aim is to use 2nd-3rd cousin matches to help connect them to your specific grandparents family lines.

If you use matches higher than 400 then you risk inaccuracy and if you go below 90 this can also compromise the results.

Once you have your list of names enter them into the first column of your table or spreadsheet.

Name Shared cMs Grandparent 1 Grandparent 2 Grandparent 3 Grandparent 4
John 389
Jason 314
Claire 299
Franklin 252
Amy 186
George 175
Jemima 103
Alan 97

Once you have all of your names inputted into your table or spreadsheet select your closest match between 90-400 centimorgans and assign them a color.

Name Shared cMs Grandparent 1 Grandparent 2 Grandparent 3 Grandparent 4
John 389
Jason 314
Claire 299
Franklin 252
Amy 186
George 175
Jemima 103
Alan 97

Change the color of the box next to that name either in the document on the computer or if you drew a graph on a piece of paper use a colored marker or pencil.

The next step is to view all the matches you share with that first individual. If the name of those matches appear in your list then turn the box next to that name the same color as seen below.

Name Shared cMs Grandparent 1 Grandparent 2 Grandparent 3 Grandparent 4
John 389
Jason 314
Claire 299
Franklin 252
Amy 186
George 175
Jemima 103
Alan 97

You now have several names of people who are likely related to grandparent 1.

The next step is to move to the next closest match you have in your list that is not related to the first name you chose. Allocate a different color to them and repeat the process as you did the first.

Name Shared cMs Grandparent 1 Grandparent 2 Grandparent 3 Grandparent 4
John 389
Jason 314
Claire 299
Franklin 252
Amy 186
George 175
Jemima 103
Alan 97

Ideally once you have done this you move on to the next closest match that has not been allocated a color and do the same. The ultimate aim is to have four groups each with their own color that clearly are related to your different grandparents.

Name Shared cMs Grandparent 1 Grandparent 2 Grandparent 3 Grandparent 4
John 389
Jason 314
Claire 299
Franklin 252
Amy 186
George 175
Jemima 103
Alan 97

If all goes well hopefully you will have something that looks like the table above.

Can You Use Matches Under 90 Centimorgans?

I know that some people have a lot of DNA matches while others have a lot less. You might not have many matches between 90-400 centimorgans so doing the Leeds Method might not be that easy. Although it is optimum for you to use matches over 90 centimorgans there is some leeway if needed.

It is obviously not optimal to include matches below 90 centimorgans but there are some instances of people having a measure of success including cousin matches as low as 70 centimorgans. The results may be a little less accurate but if you are short of names to make up the list it is worth trying to add lower matches.

It’s Not a Perfect Science

I was successful with my use of the Leeds Method. I guess I was fortunate to have just enough matches in the right shared DNA range. It is however not always perfect for everyone. You may encounter people who match up with two colors.

It is not unusual to find one person who you share DNA with who also shares DNA with cousin matches from different family lines. This may indicate endogamy or perhaps that shared match is related to this person through a family line that is not connected to you.

There are so many factors that can make it hard to get a perfect result from the Leeds Method but if you use it correctly you will get some level of success.

Conclusion

The Leeds Method is a potentially valuable tool that can help you arrange your DNA matches into groups. At its best this has been used to identify unidentified parents and at its worst you can at least perhaps determine which matches share a common ancestor.

If you have a reasonable number of DNA matches between 90-400 centimorgans this may be a fun and enlightening exercise. It is very simple to do and really does not take too long. So if you can give the Leeds Method a try you might be surprised what you find out.

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  • "What is the Leeds Method and How is it Used?". NameCensus.com. Accessed on July 2, 2022. https://namecensus.com/blog/what-is-the-leeds-method-and-how-is-it-used/.

  • "What is the Leeds Method and How is it Used?". NameCensus.com, https://namecensus.com/blog/what-is-the-leeds-method-and-how-is-it-used/. Accessed 2 July, 2022

  • What is the Leeds Method and How is it Used?. NameCensus.com. Retrieved from https://namecensus.com/blog/what-is-the-leeds-method-and-how-is-it-used/.