Saturday, May 7, 2016

AncestryDNA's updated matching algorithms - Some before and after analysis

Found this interesting article on the Cruwys news blog. It has some analysis of their results from the AncestryDNA algorithm update at

I am about half way through updating my personal test results after the v3 update. I can definitely see some change and some improvement in IBD matching. I am one of those who probably benefited the most with this update thanks to have tested both my parents and the implementation of their new phasing algorithm instituted with this update.

Having said that I still have false matches including a close in 4th cousin, good confidence, 29.5 cM/2 segment match that neither of my parents has.

Right now I have two support tickets into AncestryDNA Tech Support for matching issues that defy all logic. Sometimes that computer most be drinking heavily! ;-)

In case you haven't seen the new matching criteria, here is what Ancestry has posted in their help files for this v3 update.

And here are the shared cM levels for various relationships now.

I will be doing some additional updates here on the FRB Blog as I complete the updates for my testing. But in the meantime, here are some initial statistics before and after AncestryDNA v3 application.

Larry Van Horn (this is me)
Before Update: 82 Leaf Matches, 124 4th Cousins, 18 DNA Circles, 5 NADs, 111 Pages
After Update: 93 Leaf matches (+11), 146 4th Cousins (+22), 16 DNA Circles (-2), 5 NADs, 138 Pages

My Father Warner Lee
Before Update: 138 Leaf Matches, 213 4th Cousins, 10 DNA Circles, 10 NADs, 160 Pages
After Update: 128 Leaf Matches (-10), 220 4th Cousins (+7), 12 DNA Circles (-2), 10 NADs, 170 Pages

My Mother Gloria Ann
Before Update: 24 Leaf Matches, 165 4th Cousins, 8 DNA Circles, 4 NADs, 107 Pages
After Update: 22 Leaf Matches (-2), 201 4th Cousins (+36), 4 DNA Circles (-4), 4 NADS, 134 Pages

My 2nd Cousin Jerilyn
Before Update: 76 Leaf Matches, 249 4th Cousins, 4 DNA Circles, 9 NADs, 205 Pages
After Update: 83 Leaf Matches (+7), 373 4th Cousins (+124), 4 DNA Circles (n/c), 9 NADs, 252 Pages

My Wife Gayle
Before Update: 269 Leaf Matches, 512 4th Cousins, 24 DNA Circles, 17 NADs, 217 Pages
After Update: 280 Leaf Matches (+11), 549 4th Cousins (+37), 21 DNA Circles (-3), 17 NADS, 238 Pages

Gayle's 2nd Cousin Bryan
Before Update: 166 Leaf Matches, 598 4th Cousins, 14 DNA Circles, 18 NADs, 232 Pages
After Update: 165 Leaf Matches (-1), 621 4th Cousins (+23), 15 DNA Circles (+1), 18 NADS, 258 Pages

Some of these numbers continue to fluctuate. Two days ago I watch the number of 4th cousins on my test page change several times during the day from 149 to 147 and back up to 149. It changed like this back and forth all day long. This morning it is back down to 147 for now.

I did lose five MRCA matches, but most were down there a bit in the weeds so to speak. Here are the casualties of the v3 update.

Moderate 5.1cM/1 8GGP Cornelius Dabney-Susannah Swann
Moderate 5.5cM/1 7GGF Heinrich Furrer-Russena Rosser
Moderate 5.7cM/1 7GGP John Chalfant-Dorothy Adams
Moderate 6cM/1    5GGM Margaret McCarter-1st husband William Motley
Good       8.8cM/1 7GGP William Hurt-Anne Stennard

Also if you have not done so be sure as soon as possible download your deleted v2 matches from Ancestry. Roberta Estes on her blog at has all the instructions to perform this function so I won't repeat it here. Remember in order to have this v2 deleted file prior to the update if you starred or noted matches, and if those matches got deleted during the Ancestry update, Ancestry created that spreadsheet file for you to download.  It’s located under your setting gear wheel, to the right of your name.

More to follow, the analysis continues . . .