Evidence

A relationship is kept with the exact passage that states it, the address it came from, when that page was retrieved, and the parser version that read it.

If a document gives only a year, the year is what is stored. A missing start or end stays unknown. Old evidence means it has not been checked recently. Age alone does not make the relationship false.

Extraction yield counts work that finished. It is not a measure of accuracy. Accuracy needs a reviewed sample, and no public accuracy figure is claimed here.