Birth and death rates are important measurements of population changes. They provide a way to compare health trends and other population information from one year to another or from one community to another. The simplest kind of birth or death rate measures the number of births or deaths in a given year for every 1,000 people. For example, the crude birth rate for the United States is about 11 births for every 1,000 people. The crude death rate is about 10 deaths for every 1,000 people. The death rate is also called the mortality rate. A condition in which the birth rate is equal to the death rate is called zero population growth.
Births and deaths can also be compared in other ways. For example, the fertility rate relates the number of births to the number of women of child-bearing age. The age-specific birth rate compares the number of births by women of a certain age to the total number of women in that age group. The infant mortality rate compares the total number of infants who die during the first year of life to 1,000 live births.
