I think I also post here for discussion on possible solution strategies etc.
I am looking for a systematic way to handle uncertain parent-child relationships in cases where historical sources only allow probabilistic estimates.
Typical situation:
A man was married three times. Based on chronology (estimated birth year of a child, marriage dates, wills, etc.), it is unclear which wife is the biological mother. The child could most likely belong to the second or third wife, but the first wife cannot be completely ruled out either. I would like to be able to assign probability values to each possible mother — for example: 60 % second wife, 30 % third wife, 10 % first wife.
In ancestor charts, ancestor lists or reports, all possible mothers (or fathers) should then be displayed together with their respective probability percentages. These probabilities should also propagate to the ancestors of these possible parents. In cases of further uncertain filiations in the line or in implex/pedigree-collapse situations (where the same person appears as ancestor through multiple lines), the probabilities should be automatically recalculated (e.g. multiplied or adjusted using Bayesian methods).
In my own research, such uncertain cases accumulate across many generations in certain ancestral lines. Due to a lack of additional sources, these uncertainties cannot be substantially reduced. This makes systematic listing and evaluation of even parts of the family tree increasingly difficult and unclear.
Current state AFAIK:
The GEDCOM standard (5.5.x and 7.x) unfortunately does not provide any field for filiation probabilities. Only qualitative indicators such as PEDI, FAMC-STAT (PROVEN/CHALLENGED/DISPROVEN), QUAY or notes are available — quantitative percentages and automatic propagation are not supported.
Gramps is known for being highly extensible through custom attributes, notes, reports and addons. In theory, this feature could be implemented as an addon or extension. However, I personally lack the programming experience to create such an addon myself.
I would like to propose this as a possible future feature or addon idea. Has anyone else encountered this need? Are there any existing approaches, partial solutions, or thoughts on how this could be implemented cleanly in Gramps?