ABOUT THIS VIDEO
In this short video John Wilmoth, director of the UN Population Division, explains to Professor Hans Rosling how the population forecasts of the UN can be so accurate. It is because the future population is determined by factors that are quite predictable, namely births and deaths. We know that people grow older, and the approximate death rates of different age groups. The number of adults and old people are therefore relatively easy to predict. It is harder to predict how many children there will be, but knowing the number of adults in reproductive age makes it possible to estimate how many babies will be born.
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John Wilmoth, Director of the UN Population Division, Professor at the Department of Demography, Berkeley CA.