indicates how fast a population increases or decreases as a result of the interplay of births, deaths, and migration during a given period of time. Where the population is closed, meaning no migration, the population growth rate is the same as the rate of natural increase, i.e., the difference between the number of births and the number of deaths during a specified period of time. The three methods for computing the rate of growth based on the assumption with respect to the change are: arithmetic change, geometric change and exponential change