Advanced Placement (AP) Human Geography Practice Exam

What is the rate of natural increase (NIR) calculated from?

1. The crude birth rate minus the crude death rate

2. The total population divided by area

3. The population growth rate divided by total births

4. The number of immigrants versus emigrants

The correct answer is: The crude birth rate minus the crude death rate

The rate of natural increase (NIR) is a key demographic measure that reflects the growth of a population over time, specifically through natural means rather than migration. It is calculated by taking the crude birth rate, which represents the number of live births per thousand people in a given year, and subtracting the crude death rate, which indicates the number of deaths per thousand people in that same year. This formula provides a clear understanding of how many people are being added to or subtracted from a population due to natural causes—births and deaths—without accounting for immigration or emigration. Thus, if the crude birth rate is higher than the crude death rate, the NIR will be positive, indicating growth, while a negative NIR signifies a declining population. The other options relate to different demographic concepts: total population divided by area pertains to population density, population growth rate relative to total births could suggest how effective births are in driving population growth, and examining the balance of immigrants versus emigrants concerns net migration rather than natural increase. These distinctions clarify why the first option accurately defines how NIR is specifically calculated.