Measuring Population Change

There are 4 main factors affecting population size:

1. Birth rate
2. Death rate
3. Immigration
4. Emigration

To measure population change one needs to know:

1. Crude Birth Rate
2. Crude Death Rate
3. Doubling Rate
4. Natural Increase Rate

The Crude Birth Rate (CBR) is the number of births per one thousand individuals in a population per year. It is calculating by dividing the number of births by the total population size and multiplying by 1000.

CBR=[(Number of Births)/(Population Size)]*1000

The Crude Death Rate (CDR) is the number of deaths per 1000 individuals. It is calculated the same as the CBR.

CDR=[(Number of Deaths)/(Population Size)]*1000

The Natural Increase Rate (NIR) is a percentage found by calculating

NIR=(CBR-CDR)/10

Doubling Time is the time in years it takes for a population to double its size.

Doubling Time= 70/NIR