Demographic Transition: From High Dirth and Death Rates to Low Birth and Death Rates

Demographic transition (DT) refers to the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrialized economic system. This is typically demonstrated through a demographic transition model(DTM). The theory is based on an interpretation of demographic history developed in 1929 by the American demographer Warren Thompson (1887–1973).[1] Thompson observed changes, or transitions, in birth and death rates in industrialized societies over the previous 200 years. Most developed countries are in stage 4 of the model; the majority of developing countries have reached stage 3. The major (relative) exceptions are some poor countries, mainly in sub-Saharan Africa and some Middle Eastern countries, which are poor or affected by government policy or civil strife, notably Pakistan, Palestinian Territories, Yemen and Afghanistan.[2]
A correlation matching the demographic transition has been established; however, it is not certain whether industrialization and higher incomes lead to lower population or if lower populations lead to industrialization and higher incomes.[3] In countries that are now developedthis demographic transition began in the 18th century and continues today. In less developed countries, this demographic transition started later and is still at an earlier stage.[4]

Demographic change in Sweden from 1735 to 2000.
Red line: crude death rate (CDR), blue line: (crude) birth rate (CBR)
The transition involves four stages, or possibly five
In stage one, pre-industrial society, death rates and birth rates are high and roughly in balance. All human populations are believed to have had this balance until the late 18th century, when this balance ended in Western Europe.[5] In fact, growth rates were less than 0.05% at least since the Agricultural Revolution over 10,000 years ago.[5] Birth and death rates both tend to be very high in this stage.[5] Because both rates are approximately in balance, population growth is typically very slow in stage one.[5]
In stage two, that of a developing country, the death rates drop rapidly due to improvements in food supply and sanitation, which increase life spans and reduce disease. The improvements specific to food supply typically include selective breeding and crop rotation and farming techniques.[5] Other improvements generally include access to technology, basic healthcare, and education. For example, numerous improvements in public health reduce mortality, especially childhood mortality.[5] Prior to the mid-20th century, these improvements in public health were primarily in the areas of food handling, water supply, sewage, and personal hygiene.[5] Interestingly, one of the variables often cited is the increase in female literacy combined with public health education programs which emerged in the late 19th and early 20th centuries.[5] In Europe, the death rate decline started in the late 18th century in northwestern Europe and spread to the south and east over approximately the next 100 years.[5] Without a corresponding fall in birth rates this produces an imbalance, and the countries in this stage experience a large increase in population.
In stage three, birth rates fall due to access to contraception, increases in wages, urbanization, a reduction in subsistence agriculture, an increase in the status and education of women, a reduction in the value of children's work, an increase in parental investment in the education of children and other social changes. Population growth begins to level off. The birth rate decline in developed countries started in the late 19th century in northern Europe.[5] While improvements in contraception do play a role in birth rate decline, it should be noted that contraceptives were not generally available nor widely used in the 19th century and as a result likely did not play a significant role in the decline then.[5] It is important to note that birth rate decline is caused also by a transition in values; not just because of the availability of contraceptives.[5]
During stage four there are both low birth rates and low death rates. Birth rates may drop to well below replacement level as has happened in countries like Germany, Italy, and Japan, leading to a shrinking population, a threat to many industries that rely on population growth. As the large group born during stage two ages, it creates an economic burden on the shrinking working population. Death rates may remain consistently low or increase slightly due to increases in lifestyle diseases due to low exercise levels and high obesity and an aging population in developed countries. By the late 20th century, birth rates and death rates in developed countries leveled off at lower rates.[4]
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 Thailand have passed through the Demographic Transition Model (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.

This is principally a thesis that postulates that population patterns reflect a society's level of technology development and this is mainly projected through four phases/stages.
Stage one: Pre-industrial Societies
This society is characterised by increasing population since birth rates was high and children was considered to have considerable economic value, especially to help in the production of goods and services with the family business (cottage industry). Moreover, this period was marked by absence of conception to regulate births and little medical competences and technology to reduce escalating death rates and low life expectancy. This eventually neutralised high birth rates.
Stage two: the onset of industrialisation
This period is denoted by mass production of food production, medical development and advancement and rural-urban migration. Food supply was expanded and science was able to combat diseases. Death rates fell sharply while birth rates remained high and this resulted in rapid population growth.
Stage three: a mature industrial economy
Birth rates stated to drop within this period as fertility patterns also fell with education due to increasing use of contraception and protective sex, and working women. Moreover, children are no more of economic importance as it was in pre industrial era but rather an economic burden. In fact, improved living standards have increased the cost of raising them and thus there are lesser children (an average of two/three) per family.
Stage four: post industrial economy
Birth rates continue to fall and life expectancy to sustain itself. In fact, dual income family is also increasing the norm and parents are more likely to have lesser children.

Stages
Level of technology
Population growth
Characteristics of population trends
Stage one: pre-industrial societies
Pre industrial Death rates neutralize birth rates slow Stage two: the onset of industrialisation
Early industrial
Increasing birth rates and decreasing death rates
Rapid
Stage three: a mature industrial economy
Industrial
Birth rates decreased considerably, and death rates as well
Slow
Stage four: post industrial economy
Post industrial

Birth rates and death rates very low- resulting in ageing population

Very slow

Adapted from Macionis (pp 381, 5th edition, 2000) Criticism of Demographic Transition Theory
This theory is supportive to modernisation theories, which stipulates that industrialisation can solve fluctuations of their population. However, dependency theorists have put forward that unequal distribution of the world's wealth and resources is dividing the planet into a group of industrialised haves and unindustrialised have-nots. In fact, population control cannot solely reside in technology (Macionis, 2000).