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Certainty in Family Trees.


Staff member

I suppose a lot of you have come across very strong evidence in ancestor findings and ,ie, two people with a rare surname in the same area but you cannot pin down a relationship but have huge assumptions, or a lot of conjecture in a potential ancestor like his name appearing on marriage certs of ancestors and appearing as death cert informants or being the right age to be the father of an ancestor as he has similar names and occupations on a baptism or marriage cert. You often wonder if he is the right one but cannot get that final 100% confirmation.

EXAMPLE: John Cross is baptised, son of William and Susan Cross, he later marries and one of the witnesses is Susan Dawson, and you know that this witness has the same forename as John Cross's mother but different surname, and you find through censuses that Susan Dawson is of very similar ages to be the mother of John Cross, and this lady was also the informant on death certificates of Johns wife or baby, and Susan Dawson had a son with matching firstname and age to John Cross's younger brother Frederick, then that is a very strong suggestion that the mother Susan remarried after the death of Johns father William but cannot yet find a remarriage or a new piece of evidence to prove Sus Cross and Sus Dawson was the same person all along. You wonder if you should add her to your tree or not.

You then compare it against other scenarios and find that her being a candidate for the mother is the likliest scenario then that is good. Often you have to use the phrase "too much of a coincidence" to help your logic.

Sometimes you have to work on balance of probabilities and gut instincts as 100% certainty in family trees can be hard to achieve some people have said. Wouldnt you agree?

Yes Ben, I agree.
I have adopted the strategy and added the person to my tree, but knowing i am only 99.9% sure.
And on ancestry, you get 'hints' of others with the same relation or other entries in places that I had not imagined.

I have not been let down yet.


Judges in courts often only have 85% certainty but still manage to convict someone or settle a dispute on the likelihood of the evidence.

In genealogy you often have to use gut instinct in this game on 99% certainty.