The future size of a population depends on a range of functions. Thus:
Pt+1 = Pt + (B − D)+(1 − E)
where Pt and Pt+1 are the sizes of population in an area at two different points in time, t and t + 1 are those points, B is the birth rate, D is the death rate, I is the immigration, and E is the emigration. For an example of its use, see Roos (2005) J. Econ. Geog. 5, 616.
Subjects: Earth Sciences and Geography.