The Crude Birth Rate and Crude Death Rate are both measured by the rate of births or deaths respectively among a population of 1000. The CBR and CDR are determined by taking the total number of births or deaths in a population and dividing both values by a number to obtain the rate per 10000.
For example, if a country has a population of one million and 15,000 babies were born last year in that country, we divide both the 15,000 and 1,000,000 by 1000 to obtain the rate per 1000. Thus the Crude Birth Rate is 15 per 1000.
The Crude Birth Rate is called "crude" because it does not take into account age or sex differences among the population. In our hypothetical country, the rate is 15 births for every 1000 people but the likelihood is that around 500 of those 1000 people are men and of the 500 who are women, only a certain percentage are capable of giving birth in a given year.
Crude Birth Rates of more than 30 per 1000 are considered high and rates of less than 18 per 1000 are considered low. The global Crude Birth Rate in 2005 is 20.15 per 1000.
In 2005, Crude Birth Rates ranged from 8.33 per 1000 in Germany to 51.33 in Niger. The CBR in the United States in 2005 was 14.14 per 1000. Many African countries have very high Crude Birth Rates and women in those countries have a high Total Fertility Rate, meaning they give births to many children in their lifetime.
Learn more about Crude Death Rates on Page Two.