Natural Increase

Abstract

‘Natural increase’ (normally computed per thousand of the population so as to allow easy comparison between populations of different sizes) is calculated by taking the difference between the ‘crude birth rate’ of a population and its ‘crude death rate’. The ‘crude birth rate’ is the number of births in any year in an area, divided by the population and multiplied by 1000. The ‘crude death rate’ is computed in a similar way. At times, both these indicators can be misleading or inadequate, particularly during periods of rapid demographic growth when population age structures become skewed towards younger age groups. Crude rates nevertheless provide useful and widely available clues about the relative importance of fertilty and mortality in overall population change.