Demographic Transition Theory

Demography transition theory is known scientific theory and modern concept in the field of population study. This theory developed on the basis of real and historical events than other theories. This theory developed from the experience of developed industrial western countries but this is important for developing countries as well. Transition of population may call the revolution in population or demography cycle. It is also call the complete expansion describe from high stage to low stage of population. In the high stage showed there was high birth rate and high death rate so population is stable and low stable stage shows the low birth rate and low death rate so population growth is stable.

Landry was the first person who described the term of demographic transition theory in 1909 and in 1929 Warren Thomposn described more as theoretically that relates the growth of population to the health of economy the population was passing through.  After than in 1945, Frank Notestein tried to explain why change in birth rates differs from one country to another. He drew the attention of the learner how religious preaching, moral codes, social laws and regulations, education, customs, structure of family etc. in the underdeveloped countries encourage high birth rate. To check decline in population as a result of high death rate, high birth rate started was necessary under the prevailing social systems. The religious and social structure was tares started loosing relevance as death rates started to decline. The structure against birth rate control was either lifted as certainty about better health and long life gradually became a reality. Birth rates started to fall even in orthodox societies. He argued that high birth rate in underdeveloped countries were due to three fundamental reasons- high death rate, lack of enough opportunity to accomplish one’s aspirations and the economic value of children.

If negative factors were responsible for pulling down birth rates in the developing countries, a cluster of positive factors brought down birth rates in the industrially developed countries. Notestein drew attention to such issues as fast enlargement of urban areas, the increasing and ever changing character of urban policy, evolution of an
urban-centric culture in which the extended family system lost much of its relevance. High personal aspiration was at the heart of this urban-centric culture. Large families are not only expensive; they act as obstacle to go beyond the limits of traditional beliefs and sentiments. Notestein wrote another article in 1953 where he asserted that the
urban-centric industrial culture was at root of declining birth rate. The increased use of technology-driven industrial culture was at the root of standard of living and made life extremely fast and competitive.

The transition theory state industrialization brings down death rate first in entire countries, birth rates decline much through prevention of death and adoption of technology for birth control. There is always a time gap between drops in death and birth rates. Because of this time lag, the population expands. Before the transition begins, the population remains almost stationary by the cause of very death and birth rates. Some essential similarities in social and economic setting were observed in all developing countries-Pressure of population, low productivity, excessive dependence on agriculture sector, low level and poor technology, poor communication and transportation network, good or bad condition to public health and sanitation, poor health situation, dearth of preventive medicine and high birth rate and death rates. Nutritional deficiency and inadequate food supply not only are cause of high death rate and morbidity, often are responsible for fluctuation in population growth rates.

Thomson and Notestein have presented four stage of transition.

1. There is high birth rate and high death rate in the first stage.
2. There is high birth rate but declining the death rate.
3. There is declining both birth rate and death rate.
4. There is very low death rate and but larger than birth rate.

The first stage described in the transition theory is similar to old balance. The countries, which in the recent past were in this stage, were mostly dominated by local resident, still adhering to old traditions and culture. Nearly total dependent on agriculture, these countries had very high birth rate and death rates. Malnutrition and lack of health awareness played vital role for high death rate, especially infant and child mortality. They lacked the skill and know how needed to tackle epidemic, famine, war and natural disaster- the population grew. The possibility of a high growth is embedded in the old balance.

The second stage the death rates started to decline but birth rates continued at the same level or declining slowly compared to the decline in death rate. Europe was initiated in the agricultural revolution of the 18^th century. The increased available of food, improvement in transportation facilities and public distribution system, health awareness and supply of safe drinking water were some of the key factors responsible for the checked the death rate, especially children in these countries.  Slow decline of birth was often the cause of inertia and faith in traditional values. The decline of death rate was basically a physical phenomenon, while birth, though a physical phenomenon, is socially and culturally determined. The back of cultural induces considerable gap between death and birth rate. In this transition period, the yearly natural increase could be 2-3 percent or even higher. As a result of fast growth of population, this period is often called the stage of population explosion.

At the last of 19^th century, most of countries were in this stage. The countries where death rates could be contained very effectively but not much progress had made in curtailing birth rate, their population really exploded. This was experienced in many of the Latin America, South European, East and South Asian countries and Africa. This explosive growth may be seen as a prelude to industrialization. Many European countries entered stage 2 long before others. Europe passed through stage two before the medical advances of the mid-20^th century, reduction of mortality in Europe were mostly through the improvement in water supply, food handling and general personal hygiene following the lead from growing scientific knowledge of the cause of diseases and the improved education and social status of mothers.  Europe, North America, Oceania and Japan have already in the third stage of leaving it. The populations of these countries are growing at 0.5 % per year.  

The developed countries already have achieved the balance between birth and death rate. The population is stationary, but the size is very large and all the potential energy expanded. Both birth and death rate are nearly at their biological minimum. In the some countries birth rates went below death rates resulting in negative growth. Theoretically, the fourth stage is possible. It is possible to bring fertility down to zero, but the same cannot happen to mortality. By the cause of rapid decline in mortality are almost the same in all developing countries. But the same can't say about in birth rate.

The countries that has already in the third stage shown certain common characteristics full literacy, high productivity and stable economy, very high standard of living and Total Fertility Rate in these countries have already under replacement level. Communicative and non-communicative diseases had been the major taker-of-life. Parasitic and infections diseases and diseases related to malnutrition and childbirth still dominate in many developing countries.