Demographic Transition Model is put forward by W. S. Thompson and Frank Notestein. The theory postulates a particular pattern of demographic change from a high fertility and high mortality to low fertility and low mortality when a society progresses from a rural agrarian society to urban, industrial and modern society.
The transition from high Birth Rate and high Death Rate to low Birth Rate and low Death Rate can be divided into following 4 stages:
Stage1: Primitive stage/high fluctuating stage
High and fluctuating BR and DR. DR fluctuates because of mortality due to famine, war, epidemics. Generally rural population with subsistence agriculture face the problem of survival i.e. natural factors & conflicts decide the population size.
Stage 2: High expanding phase
In this stage DR starts falling while BR is still very high hence population growth is high. Falling DR in European experience was the consequence of benefits accruing from industrial development & agriculture modernization such as better living standards, lesser famine, expansion of life’s comfort.
The same experience was replicated in the developing world but not as a consequence of industrial revolution but because of medical revolution.
Later part of 2nd phase is called as population explosion because the gap between BR & DR is highest.
Stage 3: Late expanding stage
In this stage BR starts falling and DR is all time low. In the European experience social development kept pace with economic development. On the other hand in the developing countries, fall in BR is not always attributed to social development. It is because of deliberate coercive forceful govt. policies e.g. China’s one child policy
Stage 4: low fluctuating/ stage of population stabilization
In this stage both BR & DR bottom out hence population growth stabilize. Population curve becomes S-curve. In this stage population is highly industralised and urbanised.
Most of western countries are stabilized since starting of 20th century. Population pyramid is inverted pyramid due to low BR, low DR and more aging population.
Evaluation of Demographic Transition Model:
It is one of the earliest scientific theories on demography. It provides a fair depiction of how agrarian societies transit into industrial developed societies. Idea of mortality rate falls before birth rate is right for both developed and developing countries.
However model is descriptive and does not go into analysis of how BR itself is related to poverty, lack of women empowerment.
There are enough examples where after stabilization many countries have realized rise in both BR & DR, an argument for adding stage 5 & 6, particularly in post World War II period e.g. 1950s, 60s was phase of baby boom in US and it coincided with economic depression, industrial stagnation and mass unemployment.
DTM is old school of thought where population problem & population development are population size centric. This model belongs to the time when problem of population means problem of size so it concentrated on BR & DR.
DTM therefore was prescriptive of controlling BR, growth rate as necessary and only component in social development but contemporary scope & definition of development is far wider. In most societies more than population size, population quality- gender parity, political empowerment, livelihood security, and nutrition security are more important than BR alone.
In fact earliest population control policies which were influenced by DTM were concerned about controlling Birth Rate & Total Fertility Rate such as target based population policy of India during emergency time whereas modern population development policies are more vocal about skill development, health of population. There is persistence shift in focus from family control program to family welfare program.
Despite all its shortcomings, the DTM theory does provide an effective portrayal of the world’s demographic history at macro level of generalization.
Some appreciation please!