Monday, October 29, 2018

How Many of my AncestryDNA Matches Have Attached Trees?

Leah Larkin did a survey of the number of attached family trees that ten people had on AncestrySDNA, MyHeritageDNA, familyTreeDNA, 23andMe and GEDMatch last week in her blog post The Glass Is More Than Half Full—2018 Version.  It was excellent work.  Please read her post for the details.

I'm still a numbers guy, so I said to myself "Randy, you old finger-and-toe-counter, how many attached trees do your AncestryDNA matches have?"  Note that I don't have enough fingers and toes to do MyHeritageDNA, FTDNA, 23andMe and GEDMatch at this time.  

I chose to count them for the top 500 of my "4th cousins or closer" (I have about 1,000 of them).  I broke down the categories different from Leah's categories.  

Here are my results for my 500 top AncestryDNA matches:

*  No Tree:                                        122 = 24.4%

*  Private Tree:                                   40 = 8.0%

*  Unlinked Tree:                             122 = 24.4%

*  Less than 10 persons:                  38 = 7.6%

*  10 to 100 persons:                        57 = 11.4%

*  100 to 1000 persons:                  65 = 13.0%

*  1000 to 10,000 persons:            43 = 8.6%

*  Greater than 10,000 persons:  13 = 2.6%

Summing up the ones with attached and readable trees, my total for AncestryDNA is only 43.2%.

My 43.2% is a far cry from Leah's number of 75.1% for the 10 persons she sampled.  Looking at Leah's methodology, it appears she counted an "Unlinked tree" in her tree criteria.  Adding the "Unlinked trees" to my "Linked trees" results in 67.6%, closer to her number.  I don't know if she counted "Private trees" or not - my total counting "Unlinked trees" and "Private trees" is 75.6%, which almost exactly Leah's number for those with trees.

I have noted that almost all of my recent "New" AncestryDNA matches have no tree or an unlinked tree, and I suspect that this number of AncestryDNA matches without attached and readable trees will continue to decline.  Back before AncestryDNA was catering only to genealogists, the number was much higher - probably over 95% in the beginning.  

I was surprised that only 11.2% of my AncestryDNA matches have an attached tree with more than 1,000 profiles, and only 2.6% have a tree larger than 10,000 profiles.  

The good news is that some of the AncestryDNA matches with an "Unlinked tree" can be analyzed using Ancestry tools by accessing their "Unlinked tree."  Some are large enough to actually find your common ancestor, and some of the "Unlinked trees" need to be "extended" using Ancestry tools to find the common ancestors.  

Blaine Bettinger recently posted Building Quick & Dirty Trees to Identify Genetic Matches on YouTube to demonstrate how to "extend" an Unlinked tree.  Here it is:

This video was really helpful to me.  I have tried it on 5 of my AncestryDNA matches with an Unlinked Tree, and have had success with three of them in a relatively short period of time.  You do have to mind the caveats that Blaine explains in the video.


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