My Mom's results finally came in, and this means that I've now tested all of my living ancestors here: Mom, Dad, and my maternal grandmother.

I was tempted to just assume that all of my matches that didn't also match my father or my grandmother must be from my maternal grandfather, but just to be safe I compared my match list to Mom's... and ended up with 1,283 matches who don't show up anywhere except on my test.

Of my 3660 matches, 27% are in common with Dad, 35% are in common with Mom, 3% are in common only with my grandmother (um...), and 35% are in common with no one. Since I can't match my grandmother without matching my mother, that's 38% of my matches that must be doubted.

It could just be that due to wobbles in measuring, a parent may sometimes come out just under the cut-off point, causing the match not to appear. (Right? When comparing my family to 23andMe matches, sometimes my shared segment appears to be longer than my Mom's.) Since all but 20 of these "false positives" are "Very Low Confidence," perhaps that's the case. (Fifteen are just Low, and five are Moderate. Nothing higher.) What a SPLENDID reason for Ancestry to provide a chromosome browser. ;)

And here's another good reason: as discussed elsewhere in this forum, not all of our hints are currently showing up. However, I checked my nine visible hints to Very Low Confidence matches to see if any were on the "only me" list. Three of them were. (I'll be curious to see if this 33% fail rate holds up once all the hints are back.)

Of course this is just the nature of the test and not an issue with Ancestry. My Dad's 23andMe results came in a few days ago (it's been a busy week!), and I just checked and can see that several of my matches don't have a "M" or "P" assigned. 23andMe's stupid RF cap blocks me from seeing as many distant matches as Ancestry shows, but of the matches I can see, about 19% don't match either parent.

I don't want to discourage anyone from investigating low confidence matches or enjoying hints - with the usual grains of salt - but I thought I should share my experience. Even though I've read and reread Ancestry's pop-up help about match confidence over the past year, I just didn't expect 38% of my matches to go *poof!*.