Demographic Transition Theory

The demographic transition theory studies the relationship between economic development and population growth. It discusses about changes in birth rate and death rate and consequently growth rate of population in assonance with the process of growth and development. It is also used to describe and predict the future population of any area. The theory tells us that population of any region changes from high births and high deaths to low births and low deaths as society progresses from rural agrarian and illiterate to urban industrial and literate society. These changes occur in stages which are collectively known as the demographic cycle. There are four stages of demographic transition related to the state of economic development.

First Stage or Stage of High Birth Rate and High Death Rate

In first stage, the country is at low level of economic development. Agriculture is the main occupation of the people. Standard of living of the people is low. Death rate is high because of lack of medical facilities, epidemics, famines and illiteracy. Birth rate is high because of social and economic reasons. The key notable features of this stage are as follows:

• Population Pyramid in the first stage is Expanding at the bottom
• Stable population
• High birth rate, High infant mortality and High death rate = low life expectancy
• Many young people, very few older people
• High fertility rate (8+)

The first stage has high fertility and high mortality because people reproduce more to compensate for the deaths due to epidemics and variable food supply. The population growth is slow and most of the people are engaged in agriculture where large families are an asset. Life expectancy is low, people are mostly illiterate and have low levels of technology. Two hundred years ago all the countries of the world were in this stage.

Second Stage or Stage of High Birth Rate and Low Death Rate or Stage of Population Explosion

In this stage, birth-rate is high but death rate is low. It results in high growth rate of population. In this stage, income begins to rise and economic activities expand. On account of better health facilities and nourishing diet, death rate falls rapidly. Birth rate remains high due to social backwardness and limited access to contraceptives. The key notable features of this stage are as follows:

• Population Pyramid in this stage is Rapidly Expanding
• Very rapid increase in population (population explosion)
• Rapid decline in death rate but death rate remains below the birth rate
• Fertility rate remains high
• High birth rate
• High rate of natural increase
• Decline in infant mortality
• Many young people

Fertility remains high in the beginning of second stage but it declines with time. This is accompanied by reduced mortality rate. Improvements in sanitation and health conditions lead to decline in mortality. Because of this gap the net addition to population is high.

Third Stage or Stage of Declining Birth Rate and Low Death Rate

In the third stage, a declining birth rate and low death rate lead to low population growth. Along with economic development of the country, structural changes in the economy begin to take place. Large population begins to reside in urban areas. People start considering large families as liability. Consequently, birth rate begins to fall. Death rate continues to be low. Growth rate of population declines. India is passing through this stage of demographic transition. The key notable features of this stage are as follows:

• The Population Pyramid in third stage is Stationary
• Population growth slows down
• Birth rate declining rapidly
• Decline in fertility rate
• Death rate declining slowly
• Birth rate approaching death rate
• High life expectancy
• Increasing number of older people

Fourth Stage or Stage of Low Birth Rate and Low Death Rate

In the fourth stage, low birth rate and low death rate lead to Population stabilisation. In this stage, because of rapid economic development, standard of living of the people becomes very high. Quality of life is given a priority to the size of the family. The key notable features of this stage are as follows:

• Population Pyramid is Contracting
• Stable or slow population increase
• Low birth rate
• Low death rate
• High life expectancy
• Birth rate is approximately the same as the death rate
• Fertility rate is close to or below 2.1
• Many older people

In the last stage, both fertility and mortality decline considerably. The population is either stable or grows slowly. The population becomes urbanised, literate and has high technical knowhow and deliberately controls the family size. This shows that human beings are extremely flexible and are able to adjust their fertility. In the present day, different countries are at different stages of demographic transition.