Zero Population Growth
Heather M. Griffiths
The concept of zero population growth (ZPG), first used by Kingsley Davis (1908–97), is a condition in which the number of children born, combined with the number of people who immigrate, is equivalent to the number of people who die, combined with the number of people who emigrate. Under this condition, the population neither expands nor contracts. It is more simplistic, but less accurate, to calculate the ZPG using a country's total fertility rate (TFR) of 2.1 or lower as a benchmark. The TFR, or number of children a woman has in her lifetime, however, is only one indicator of population growth. Demographers, environmentalists, and ...