However, this evidence depends on the existence of a late-life plateaus and deceleration that can be explained, in humans and other species, by the existence of very rare errors. Age-coding error rates below 1 in 10,000 are sufficient to make artificial late-life plateaus, and errors below 1 in 100,000 can generate late-life mortality deceleration. These error rates cannot be ruled out by examining documents, the standard, because of successful pension fraud, identity theft, forgeries and errors that leave no documentary evidence. This capacity for errors to explain late-life plateaus solves the "fundamental question in aging research is whether humans and other species possess an immutable life-span limit", indicating that humans do indeed have a lifespan limit.