Most lineage society applications rely heavily on the use of direct evidence, the statements of birth, death, and marriage date and place and family relationships in original documents. Sometimes, however, those statements don’t exist. If indirect evidence, evidence that provides relevant information about the question but does not actually answer it, can be used to document birth, death, marriage and relationships, the link to the qualifying ancestor can still technically be documented. But how does the society handle the information?
It depends. Most societies do allow the submission of a proof argument, a written argument showing that the indirect evidence supports the conclusion that you believe it to draw. They often refer to a proof argument as an analysis. That being said, there are some limitations placed on when an analysis can be used, the type of argument that can be made, and the length of the analysis. Short arguments that offer direct evidence connecting a sibling to the parent and the ancestor to a sibling are often welcomed. Longer arguments relying on “rule out” cases are accepted far less often.
When in doubt, first, consider discussing the issue with the society’s registrar or genealogist. At minimum, they should be able to provide you with the relevant guidelines. Second, think about publishing. Academic proof arguments, once published, are typically treated by the society as a publication – an entirely different status.