Understanding matching for Shared Ancestor Hints in AncestryDNA?

Question

This may be related to Why might number of Shared Ancestor Hints go down on AncestryDNA? but I think it is a more specific question, and so, at least for now, I do not think that it should be considered a duplicate.

On Ancestry.com when I click the DNA link at the top I am currently told that I have 25 Shared Ancestor Hints and 130 4th cousins or closer. Amongst my 4th cousins or closer is an individual X with whom I have 36 centimorgans shared across 3 DNA segments. X is not amongst my Shared Ancestor Hints, and I am trying to determine the reason for that.

• Both X and I have public trees with around 2,000 or more people in them.
• X has an ancestor named Jane Harvey:
  • B: 6 Dec 1759 in , Devon, , England
  • D: 14 Sep 1824 in Totnes, Devon, England
• I have an ancestor named Jane Harvey:
  • B: Bef 6 Jun 1759 in Totnes, Devon, England
  • D: 14 Sep 1824 in Totnes, Devon, England
• X has an ancestor named James Murch:
  • B: 5 Aug 1757 in Totnes, Devon, England
  • D: 1810 in Totnes, Devon, England
• I have an ancestor named James (II) Murch:
  • B: 05 Aug 1757 in Totnes, Devon, England
  • D: 31 Dec 1810 in Totnes, Devon, England

Is the way that I have named James Murch as James (II) Murch (whose older brother James died a week after being baptised) the likely reason for X not showing up in my Shared Ancestor Hints or is it something about the dates and locations of the events listed that may be preventing it?

Answer 1

Ancestry says (about Shared Ancestry hints):

Ancestry compares the information in your tree to your match's tree to identify common ancestors. As a result, the more complete your tree is, the more likely you are to receive shared hints. When a potential common ancestor is identified, we compare several aspects of the person in each match's tree: their name, birthday, locations, parents, spouses, and children. If everything lines up, a hint is created.

It's therefore probable that the correspondences between your common ancestors in your trees are not close enough and/or many enough to trigger the hint. (Ancestry don't publish the algorihtm they use, so it's not possible to know exactly what needs to be done to trigger the match).

As another example of this, my half-first-cousin (same grandfather, different grandmother) has just had her DNA tested. We know we're related because the paper trail and family stories confirm that my grandfather bigamously married her grandmother. However, Ancesty doesn't offer a hint 'leaf' even for so close a relationship -- perhaps because her grandfather is recorded with a middle name and mine is not, and the birth dates are slightly different (he lied at his second marriage).

I would try removing the (II) from your James Murch and see what happens. The dates for Jane Harvey might be equally problematic -- it may be that patradoxically you need to make the birth for your Jane Harvey less accurate (1759 not bef 6 June 1759); or it may be that getting James Murch to match will make the Janes match as well.