# How do you estimate world population of 1000 years ago?

I watched this video and now I am curious. They show the population of the world 1000 years ago and they also have a population distribution map. How do you estimate something like that? And is the distribution map just a guess or is there some reasoning involved? And if I were to do something similar with my country's data where would you suggest I start?

• Questions should as far as possible be self-contained and not depend on reading an external source (which is not under the control of CV, clearly). Can you restate your question to emphasise the statistical aspects and to summarize the relevant content of the video?
– Nick Cox
Dec 15, 2016 at 17:47

My understanding is typically:

• For hunters & gatherers, and pastoralists, population density is assumed to fall within a known range for such peoples today.
• For farming societies, their large cities can be estimated(pdf) based on the (geographic) size and habitation density. Their smaller towns can be estimated similarly, and then the total population of those estimated based on the known density of such towns.
• Some ancient societies actually produced Censuses for their own (usually military and/or taxation) purposes. For example, we know from a 6th Century BCE census that the Kingdom (City) of Rome had 80,000 men of military age. Adding a small percentage for those out of that age, then doubling that to count the women shouldn't get you too far off its actual population.
• The main purpose of censuses was not military but tax purposes. And tax records is one of the main sources for estimation of size of population in civilized societies.
– Alex
Dec 15, 2016 at 19:13
• It would be nice to know some sources/examples for the first two points. Dec 15, 2016 at 19:15
• @Alex - You are right, of course. Updated.
– T.E.D.
Dec 16, 2016 at 0:30
• @taninamdar - The second I've seen done in several discussions (/arguments) on the population of excavated cities like Cahokia. I added a link (PDF, sorry) that discusses this. The first I think is common knowledge(?)
– T.E.D.
Dec 16, 2016 at 0:39
• Thanks! I was interested in the techniques, that's all! :-) Dec 16, 2016 at 3:08