The term fertility, as used in the social sciences, refers to the actual births of children, and the fertility rate attempts to gauge the number of children being born into a population. The simplest of these rates is the crude birth rate (CBR), which is the number of live births in a year divided by the total midyear population. It is usually multiplied by 1,000 to reduce the number of decimals. The CBR is “crude” because it does not take into account which groups of people in the population were actually likely to have births and ignores the age structure of the population, which greatly affects how many live births can be expected in a given year. Thus, the CBR (which is sometimes called simply ...