Thursday, June 2, 2016

AncestryDNA New Ancestor Discoveries (NADs) Update

I received this information from AncestryDNA today about the New Ancestor Discovery feature:

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Wanted to give you all an update on a change to New Ancestor Discoveries following feedback from the community. In order to determine New Ancestor Discoveries, we created an algorithm with criteria that connects people to DNA Circles based on their DNA matches. This algorithm was created last year when we launched New Ancestor Discoveries and with the rapid growth of the DNA database, we are finding it needs to be updated. As DNA Circles get larger and more DNA matches are delivered, more people are connecting into the DNA Circles, which results in more New Ancestor Discoveries, but with a decrease in accuracy. 

So, we are updating the criteria to make it more conservative and increase the accuracy of New Ancestor Discoveries. So, you’ll need more connections into a DNA Circle to get a New Ancestor Discovery. These updates will result in a significant decrease in the number New Ancestor Discoveries, but with an increase in accuracy. Some populations may experience larger decreases. We will continue to monitor and adjust this as necessary to ensure these provide meaningful discoveries for our members.

This update to the algorithm is currently happening and you can see changes as soon as today or tomorrow. Previously, you needed to match at least 2 members of a known DNA Circle to be given a New Ancestor Discovery. Now, users must match at least 3 members of a small (15 members or less) DNA Circle to be given a New Ancestor Discovery. For larger DNA Circles (16+ members), users must match 20% of that Circle to be given a New Ancestor Discovery. For example, if there is a DNA Circle of 10 people, you will need to match at least 3 people to get a New Ancestor Discovery. And if there is a DNA Circle of 30 people you will now need  to match 6 people instead of 2. 

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Last week, I had 25 New Ancestor Discoveries (see Now I Have 25 New Ancestor Discoveries! Really?), and now I have only 5 after this latest update.


I don't' believe that any of these 5 are my ancestors, although they may be distant cousins with a common ancestor back 10 to 12 generations from me.  The amount of shared DNA with the DNA matches are usually in the 8 to 10 cM range on only one segment.  

I still have six DNA circles that haven't changed over the past year or so.  These are for ancestors of mine.

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Copyright (c) 2016, Randall J. Seaver

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3 comments:

L Smith said...

I went from 28 new Ancestor Discoveries to just 6. I still see no connections based on both names and locations. I have 2 DNA circles currently. I used to have 3. I can see family connections within the circles.

J said...

I've seen a reduction and that's good. My matches are all spouse pairs now. 3 of the pairs appear unconnected but the other 3 match enough geographically that I think I'll delve in further.

Christine said...

I've had no success with these Ancestor Discoveries. They need to focus on a chromosome browser instead.