What is the term for a population growth rate of zero, where births and immigrants equal deaths and emigrants?

The term that describes a population growth rate of zero, where the number of births and incoming immigrants balances out the number of deaths and outgoing emigrants, is zero population growth (ZPG). This concept indicates a state of demographic stability, where the population size remains constant over time.

In a situation of ZPG, the fertility rate typically falls to the level that sustains the existing population without growth, which is often around the replacement level of approximately 2.1 children per woman, factoring in mortality rates. This condition can arise in various scenarios, including advanced economies where family planning and access to contraception may lead to lower birth rates, as well as in populations experiencing significant out-migration.

Understanding zero population growth is essential for demographers, sociologists, and policy makers as it indicates potential shifts in social structures, resource allocation, and economic growth.