THE THEORY OF DEMOGRAPHIC TRANSITION

The theory of Demographic Transition also known as Population Stage, Population Cycle, Demographic Cycle or Vital Revolution explains the effect of changes in fertility and mortality rate on the natural increase of the population. This model, in its original form, birth propounded by W.S. Thompson (1929) and F.W. Notestein (1945) later on revise version were presented by Karl Sax, G.T. Trewartha and C.P. Blacker etc.

According to E.G. Dolan, Demographic Transition refers to the population cycle begins with the fall in death rate, continues with a phase of rapid population growth, and concludes with a decline in birth rate.

The demographic transition model postulates are unique pattern of transformation from high fertility and high mortality to low fertility and low mortality when a society progresses from the rural agrarian and illiterate state to urban, industrial and literate state.

This theory involves the following three hypotheses in the process of transformation:

1. The declining mortality comes before declining in fertility.
2. The fertility eventually declines to match mortality.
3. The social and economic transformation of the society takes place simultaneously with the demographic transition

G.T. Trewartha in his book, ‘A Geography of Population; World Patters’ published in 1969, expressed his views that biologically man is the same engaged reproduction, but culturally he is diverse. Therefore, the various countries of the world are in the different stage of demographic transition.

W.S. Thompson and F.W. Notestein suggested three stages in the demographic transition model. But according to Karl Sax and C.P. Blacker presented four of five stages of demographic transition model respectively. The different stages and their various names suggested by different scholars are given in the following table. 

Table: Stages of Demographic Transition According to Different Scholars.

Name of Scholars	Stages of Demographic Transition
W.S. Thompson	Pre-transitional Period
	Transitional Period
	Post-transitional Period
F.W. Notestein	High Growth Rate
	Decreasing Growth Rate
	Population Decreasing
G.T. Trewartha	Pre-industrial
	Early Western
	Late Western
Karl Sax	High Stationary Stage
	Early Expanding Stage
	Late Expanding Stage
	Low Stationary Stage
C.P. Blacker	High Stationary Stage
	Early Expanding Stage
	Late Expanding Stage
	Low Stationary Stage
	Declining Stage

A brief description of the trends of fertility ad mortality and the socio-economic status of the society in the five phases identified by the C.P. Blacker and observation made by different scholars is given as below:

Fig: Population Transition Model

Characteristics of Different Stages of Demographic Transition Model: -

Stage I: -

• Fertility and mortality are over 35 per thousand.
• Stable or slow population growth
• It occurs in primitive agrarian rural society.
• It prevails due to high infant mortality, low productivity level, religious orthodoxy, illiteracy and poor health care.
• Large families are considered as assets.
• About 200 years ago, all countries were in this stage but not a single in current time.

Stage II: -

• High fertility of over 30 per thousand and a sharply reduced mortality rate.
• Improvement in health and sanitation.
• Agricultural improvement (crop rotation, selective breeding and seed drill technology).
• Increase in food supply.
• Life expectancy starts improving.
• Population expansion takes place.
• Countries in this phase: Yemen, Afghanistan, Bhutan, Laos etc.

Stage III: -

• Low death rate and birth rate diminish.
• Enhance economic condition, education, access to contraception.
• Population moves towards stability through a decline in birth rate.
• Increasing industrialization and urbanization.
• Children are burden rather than assets.
• Countries: Costa Rica, El Salvador, Mexico, Columbia, Ecuador, Philippines, Indonesia, Malaysia, Turkey, Tunisia, Algeria, Morocco, Lebanon, India, South Africa, and Saudi Arabia etc.

Stage IV: -

• Birth rate death rate ad death rate are low, stable population.

• Highly urbanized and industrialized society.

• Countries: USA, Canada, Australia, New Zealand, Brazil, Sri Lanka, South Korea, Singapore, Iran, China, Turkey, Thailand and majority of Europe etc.

Stage V: -

• In this stage the birth rate is greater than the death rate.

• Fertility rate below replacement level (2.1).

• Population aging and population decline occurs.

• Highly urbanized and industrialized socio-economic condition.

• Countries: Sweden, Germany, Norway, Finland etc.

Criticism:

The theory of transition model has been criticised by a number of scholars. Some of the major limitation of this model are as following:

According to some critics the sequence of stages in the demographic transition model is not universally correct. Because according to them, in the Eastern and Southern Countries of Europe Specially in Spain.

According to Notestein, fertility firstly declines in urban areas followed by rural areas, but everywhere is not true, i.e. the fertility rates I the rural areas of Sweden and France decline simultaneously with the fall of fertility.

The model fails to explain the causes of fall of fertility rate in various countries of Europe.

The theory excludes the impact of migration on the growth rate on population.

There is more emphasis on economic factors transforming the society rather than on social factors.

Whatever may be the drawbacks of this model, it helps us not only in understanding the history of the population growth of the developed countries as well as of the under developing countries but also paves the way to explain the presentence of population growth and also for forecasting the growth rate in future for framing the population policies to get the fruits of the demographic dividend.