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In demography, the term demographic transition is a theory describing a possible transition from high birth rates and death rates to low birth and death rates as part of the economic development of a country from a pre-industrial to an industrialized economy. Usually it is described through the "Demographic Transition Model" (DTM) that describes the population changes over time. It is based on an interpretation begun in 1929 by the American demographer Warren Thompson of prior observed changes, or transitions, in birth and death rates in industrialized societies over the past two hundred years. Most developed countries are already in stage four of the model, the majority of developing countries are presumed to be in stage 2 or stage 3, and no country is currently still in stage 1. The model has explained human population evolution relatively well in Europe and other highly developed countries; the model is often applied to lesser developed countries to allay concerns regarding overpopulation, without proof that the underlying dynamics will allow these countries to trace similar evolution paths as the European and other Western countries. Origins Of DTM The idea of DTM was first put forward by Warren S. Thompson in 1929. He divided the world into three major groups, namely North & Western Europe, Central and Southern Europe, and Rest of the world. This theory was later developed by F. W. Notestein in 1945. Notestein suggested that there was a relationship between population change and industrial development. His model was based on population changes in several industrialized countries in Western Europe and North America. It also suggested that with time, countries go through a linear evolution from traditional, non-industrial society to a modern, industrial and urban one. Summary of the theory The transition involves four stages, or possibly five. As with all models, this is an idealized picture of population change in these countries. The model is a generalization that applies to these countries as a group and may not accurately describe all individual cases. The extent to which it applies to less-developed societies today remains to be seen. Many countries such as China, Brazil and India have passed through the DTM very quickly due to fast social and economic change. Some countries, particularly African countries, appear to be stalled in the second stage due to stagnant development and the effect of AIDS. Stage Two in detail
Stage Three in detail Stage Three moves the population towards stability through a decline in the birth rate. There are several factors contributing to this eventual decline, although some of them remain speculative: The resulting changes in the age structure of the population include a reduction in the youth dependency ratio and eventually population aging. The population structure becomes less triangular and more like an elongated balloon. During the period between the decline in youth dependency and rise in old age dependency there is a demographic window of opportunity that can potentially produce economic growth through an increase in the ratio of working age to dependent population; the demographic dividend. However, unless factors such as those listed above are allowed to work, a society's birth rates may not drop to a low level in due time, which means that the society cannot proceed to Stage Four and is locked in what is called a demographic trap. Countries that lie in this Stage include: China, South Korea, Malaysia, Brazil & South Africa Stage Five?
Applicability to Lesser Developed Countries One of the principal criticisms of the DTM is the questionable applicability to lesser developed countries, where the prerequisites for wealth and information access are limited. This is an important shortcoming, since DTM is used widely to minimize concerns regarding overpopulation and paint an exaggeratedly optimistic version of the future, without adequate basis. Neo-Malthusian objections The DTM is used to classify countries into general groups. Hence, it is unable to take into account evolutionary changes in the process of population growth and classify diverse population into distinct but coherent stages of the development process. Neo-Malthusians argue that the long-term fertility of a population depends on the most rapidly-breeding subgroups within the population. In the short term, the overall population growth rate may slow as most of the existing people have fewer children, but if a rapidly-breeding subgroup sustains its high fertility, it will eventually expand its numbers and restore the whole population to high fertility. This is similar to the evolution of resistance to pesticides in insects, and to antibiotics among pathogens: the first applications kill large numbers, but a few surviving resistant individuals may eventually make good on the losses through exponential growth. In other words, a criticism of the DTM is that it is only valid if the fertility-lowering social changes that caused the DTM in present-day industrial nations permanently lower the fertility of every subgroup within each nation. Garrett Hardin doubted that purely voluntary birth control could achieve that result; Hardin argued that voluntary birth control merely selects against the people who will use it *. Generalization from European experience The DTM is also limited in the sense that it gives a generalized picture of population change over time based on European studies, assuming that all countries would follow suit. In addition, the DTM is rigid in assuming that all countries will go through the stages 1 to 4 in that exact order. There are variables and exceptions such as war and turmoil that may lead to different results. Some countries may even skip stages. Subsistence farming and capital formation The Peruvian economist Hernando de Soto has argued that one obstacle to industrial development is that subsistence farmers can not convert their work into capital which can be used to start new businesses and trigger industrializations. He argues that these obstacles exist often because subsistence farmers do not have clear title to the land which they work and to the crops which they produce. Insufficiency of wealth effect on fertility Another limitation of the DTM is that it assumes population changes are brought about by industrial changes and increased wealth. This is not true as social changes are equally important in determining birth rates, for example, the education of women. Also, DTM assumes that the birth rate is independent of the death rate. The opposite is true. When infant mortality increases, people are more likely to have more children to replace themselves. Next, the time taken for Economically Less Developed Countries to go through the stages might be lower as there is availability of knowledge from mistakes made by Economically More Developed Countries. On the other hand, birth rates remain high in some nations such as Saudi Arabia despite great increases in prosperity. Further reading See also | |||||||||||
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