Demographic Transition

Demographic transition (DT) refers to the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrialized economic system. This is typically demonstrated through a demographic transition model. The theory is based on an interpretation of demographic history developed in 1919 by the American demographer Warren Thompson (1887–1973). Thompson observed changes, or transitions, in birth and death rates in industrialized societies over the previous 200 years. Most developed countries are in stage 4 of the model; the majority of developing countries have reached stage 3. The major (relative) exceptions are some poor countries, mainly in sub-Saharan Africa and some Middle Eastern countries, which are poor or affected by government policy or civil strife, notably Pakistan, Palestinian Territories, Yemen and Afghanistan.

A correlation matching the demographic transition has been established; however, it is not certain whether industrialization and higher incomes lead to lower population or if lower populations lead to industrialization and higher incomes. In countries that are now developed this demographic transition began in the 18th century and continues today. In less developed countries, this demographic transition started later and is still at an earlier stage.