What is it called when more people are born than die in a population, contributing to its growth?

When more people are born than die in a population, the phenomenon observed is termed natural increase. This concept is a fundamental aspect of demography, reflecting a positive difference between birth rates and death rates, which indicates that the population is growing.

Natural increase is a crucial factor in understanding population dynamics, as it directly influences long-term trends in population size, age distribution, and social structures. The demographic transition model often incorporates natural increase as a key indicator of countries transitioning from a high birth and death rate to lower rates, thereby fostering rapid population growth.

In contrast, natural decrease refers to a situation where the death rate exceeds the birth rate, leading to a declining population. Net growth could imply both natural increase and other factors like migration but is not the term specifically denoting the balance between births and deaths. Population shift typically addresses movement within populations rather than changes in their growth rates due to births and deaths. Thus, 'natural increase' accurately captures the scenario described in the question.