Per capita growth rate of a population is symbolized as "r" in population growth models. Here, "r" is the rate of change of a population on a per capita basis. The change in the population includes both an increase and a decrease in its size. The per capita growth rate is calculated by subtracting the birth rate of the population from its death rate. Therefore, r= b-d. Here, "b" is the birth rate of the population and "d" is the death rate.
