The problem, which I first noticed in the "Close Match Alerts" they they send every two or three days, was that people who tested more recently were being called as better matches than people who had tested earlier, despite what their own numbers were saying.
Here are three matches between a man named Mark and three of my siblings. My brother, whose test was received in Houston on 7 January 2017, matches Mark with 143 cM total and a longest segment of 8 cM. FTDNA calls him a "second cousin - fourth cousin."
My sister Sarajoy, who tested in July 2014, matches the same Mark with 145 cM total and a longest segment of 8 cM. FTDNA calls them "Fifth cousin - Remote Cousin."
My sister Jean, who tested in December 2014, matches Mark with 149 cM with a longest segment of 23 cM. FTDNA calls them "Third Cousin - Fifth Cousin."
Something is clearly wrong. It is as though the algorithm was changed but only for people who tested more recently.
If you look at the comments in my March blog, you will see that Lara Diamond - a serious DNA researcher by any standard - had noticed the same phenomenon.
I had some half-hearted correspondence with FTDNA's Help Desk, but it was all dismissed as the randomness of DNA. Then last winter I sat with Janine Cloud at RootsTech and got more specific. She sent me back to the Help Desk and there it remained for the last six months.
At the IAJGS Conference in Orlando, I sat with Bennett Greenspan - the Man Himself - and he asked me to forward my anecdotal data to him personally. Yesterday he acknowledged that the problem is real and that they would be addressing it, though not immediately. I'll mark it for follow-up in sixty days.
In the meanime, my second cousin Marty's test arrived in Houston this week and I'll be looking to see if his matches are significantly different from those of his sister Rhoda, who tested way back at the beginning.
Now if we could get GEDmatch to acknowledge their problems, we would be getting somewhere.
I am speaking on Thursday 7 Spetember for IGRA in Modiin at seven thirty. The address is Yigal Yadin 41, ground floor and I'll be speaking (in English) on
Lessons in Jewish DNA – One Man’s Successes and What He Learned On the Journey