Dense Populations

I’ve seen several articles recently in the mainstream media, including one from the BBC and one from Sky News, questioning which countries have had the best and worst Covid-19 policies thus far, where this information is being distilled by considering things like number of deaths, population density and herd immunity. But both articles neglect to consider this properly, because they talk about population density as if it's the same thing everywhere you go. It isn't.

Interaction rates differ from place to place once you stop thinking of population density as merely population divided by area, and herd immunity differs from place to once you consider the different dynamics of interaction and exposure. Herd immunity must, by its very nature, bring about different percentages of immunity in different areas of the land.

Frequency of interaction depends somewhat on population density, but not comprehensively. It's an error to merely calculate density by dividing the population by area. Adding 50,000 square miles of uninhabited fields is not going to have a radical effect on the Covid mixing effect in terms of population divided by area, despite causing a reduction in overall population density. And at the same time it has no tangible effect on the average density from the perspective of any one individual.

 

Further Reading: The Absudity Of The 'UK Overcrowdedness' Myth