An analysis of some aspects of population projection
The rising awareness of existing problems created by rapid population expansion has resulted in systematic investigations of the characteristics of population growth. These investigations have produced methods for projection of future populations.
Attempts have been made to project world population, but the situation is too heterogeneous to provide useful results. Population problems, although of world-wide importance, are problems of particular peoples and particular areas.
Some of the earliest methods of projection used in the United States were based on the Malthusian Law and geometric progression.Pritchett and Pearl, in the late 1800's and early 1900's, devised parabolic methods of projection. These early projections were good for short term projection but generally unrealistic for long range use.
In 1920 Pearl and Reed devised an empirical curve, later known as the logistic curve of' population growth.. This method received considerable attention. The logistic was supported by many later demographers and the resulting projections satisfied all but a few critics.
Whelpton's “analytical method,” and other similar methods, have been widely accepted. They give emphasis to birth-, death-, and net-reproduction-rates and not to mathematical growth curves.
Many of the above methods are used to make projections based on census counts to date. These projections are compared and tables used to show the results.