What’s the range of uncertainty regarding the population of the Americas in 1492? | Statistical Modeling, Causal Inference, and Social Science

A few days ago we discussed a post by historian Sean Manning who, in the context of a review of a book by economist Brad DeLong, wrote: I [Manning] don’t see much value in estimating the population of the world in 6000 BCE when we can’t agree on the population of the Americas in 1492 within a factor of 20, and took decades to agree on the population of the Roman empire under Augustus within a factor of two. I pointed this to someone by email, who disagreed with the claim of a factor-of-20 uncertainty: The lowest estimate I am aware of was A.L. Kroeber’s 8 million estimate in 1938, based on backward extrapolation from 1800s populations without any recognition of the effects of the effects of plagues on a greenfield population. Dobyns, reacting against Kroeber in 1966, pulled a 20:1 “depopulation ratio” from the first century of contact out of thin air. People who think hard about this guess at around 40 million, with some anchoring out of an unwillingness to be a weirdo, but not much. I

A few days ago we discussed a post by historian Sean Manning who, in the context of a review of a book by economist Brad DeLong, wrote: I [Manning] don’t see much value in estimating the population of the world in 6000 BCE when we can’t agree on the population of the Americas in 1492 within a factor of 20, and took decades to agree on the population of the Roman empire under Augustus within a factor of two. I pointed this to someone by email, who disagreed with the claim of a factor-of-20 uncertainty: The lowest estimate I am aware of was A.L. Kroeber’s 8 million estimate in 1938, based on bac