when calculating the rate of natural increase one does not include
Rate of natural increase In demographics, the rate of natural increase (RNI) is the crude birth rate minus the crude death rate.[1] This rate excludes population increase from in migration and out migration. When looking at countries, it gives an idea of what position in the Demographic Transition Model, but to find out how much a country is growing, the population growth rate should be observed. The Demographic Transition Theory explains the rate of natural increase relate to the economic growth.
Internal rate of return The internal rate of return on an investment or project is the "annualized effective compounded return rate" or rate of return that sets the net present value of all cash flows (both positive and negative) from the investment equal to zero. Equivalently, it is the discount rate at which the net present value of future cash flows is equal to the initial investment, and it is also the discount rate at which the total present value of costs (negative cash flows) equals the total present value of the benefits (positive cash flows).