Common Ancestors - how does this work?

[rsel]

Hi LizzieL,
   i think there are some 'strange' things going on with the Common Ancestors.  I have had a few new matches with no tree, but they have the common ancestor icon appearing. The icon then disappears a few days later. I do wonder if like 4b2 mentions they are people who deleted there trees, perhaps after initially linking to the results, and that is screwing up the Ancestry process that initially determines if a CA exists.

Richard

[LizzieL]

If my two had a tree linked then deleted it, they must have done it all in a space of 8 weeks as they weren't showing as having CAs at the end of August.
It is very curious. Maybe something to do with some people subscribing to pro-tools. I haven't yet.

[Albufera32]

Common ancestors will only appear (for you) if you have a linked family tree.

I suspect that may be why there are so many linked trees with just one person in them - it is people who actually make up their trees using an offline program, but still want to see any potential common ancestors.

Common Ancestors will appear and disappear if other people make changes to their trees (e.g. if the "link" in the common ancestor thruline is from a tree whose owner realises they have made a mistake and removes that link) or as sometimes happens, when a person who has more than one tree changes which of their trees is linked to their DNA results.

I have one particularly frustrating DNA match with a lady in Australia who has two trees and seems to periodically swap which of the two is linked to her DNA test. Judging by the composition of the two trees, I believe one is a "maternal" line whilst the other is "paternal". I say judging by the trees because in both cases the home person of the said tree (and hence the person Ancestry thinks the DNA belongs to) is dead, and has been for longer than DNA testing existed.

The truly frustrating part being that she might be a direct ancestor of my most solid brick wall.