demographic transition

Demographic transition:

The demographic transition model DT is the transition high births and death rates to lowbirth and death rates as a country developed from a ore industrial to an industrialized economic system. The theoryis based on an interpretation of demographic history developed in 1929 by the American demographer Warren Thompson 1887-1973. Thomson observed changes  or transition in birth and death rates in industrialized societies over the previous 200 years. Most developed countries are in stage 3  or 4 of the model the majority of developing countries have reached stage 2 or stage 3. In countries that are now developed this demographic transition began uin the 18th century d countries today.