The Demographic Transition Model

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The Demographic Transition Model
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What is it?

• The "Demographic Transition" is a model that
  describes population change over time. It  is
  based on an interpretation begun in 1929 by the
  American demographer Warren Thompson, of the
  observed changes, or transitions, in birth and
  death rates in industrialized societies over the
  past two hundred years or so.

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What does it look like?
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Stage One Preindustrial

• This stage is associated with pre-modern times
• It is characterized by a balance between high
  birth rates and high death rates
• There is a slow rate of natural increase, due to
  the high death rate
• Life expectancy would be short, most of the
  deaths were of children
• There was a lack of knowledge of disease
  prevention and cure, and food shortages

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Stage One Continued

• Raising a child cost little more than feeding him
• there were no education or entertainment expenses
• in equatorial Africa, there were no clothing
  expenses either
• As adults, they provide labor, carry on the
  family name, and provide insurance
• Modern Examples There are no modern examples

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Graphic Representation
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Stage Two Developing Society

• This change began with the 1st Agricultural
  Revolution
• Characterized by a rise in population
• Birth rate remains high, but death rates decrease
• The rate of natural increase is growing slightly,
  due to the lowering death rate
• Life expectancy in children increased, due to
  improvements in medical care and vaccinations

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Stage Two Continued

• Children are still considered valuable as they
  still provide labor
• Increased food production led to a healthier
  population
• Children survive childhood, and begin reproducing
  at a young age, with the same high fertility rate
  as their parents
• Modern Examples Yemen, Afghanistan, and
  Sub-Saharan Africa

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Stage Three Transitional Society

• This stage is characterized by a declining birth
  rate
• The death rate is also declining
• The rate of natural increase is increasing, as
  people are living longer
• Life expectancy is also high

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Stage Three Continued

• Explanations for the declining birthrate are
  somewhat speculative
• In rural areas, a decline in the child death rate
  mean that not as many children are needed to
  provide insurance for old age
• Increased urbanization increases the cost of
  living
• Education and living expenses increase for
  children, and they are no longer able to provide
  labor

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Stage Three Continued

• Speculative explanations
• Increased literacy and employment lower the
  expectation for childbearing as the measure of a
  womans worth
• Increased access to contraceptives allowed
  families to make decisions concerning the size of
  their families
• Modern Examples Costa Rica, Mexico, and Turkey

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Stage Four Industrialized Society

• This stage is characterized by stability.
• The birth rate is low, and the death rate is low.
• The fertility rate is below replacement levels
• There is a low rate of natural increase
• Life expectancy is extremely high, due to access
  to medical care

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Stage Four Continued

• The population is high and stable.
• Most of the females have a high level of
  education and literacy
• Children are seen as financial liabilities, not
  assets
• Modern Examples United States, Canada, and
  Australia

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Stage Five Deindustrialized Society

• This last stage is somewhat controversial, as not
  all geographers agree that there is a stage five
• This stage is characterized by a move from an
  industrial society to a service based society
  (secondary to tertiary sectors)
• Characterized by an extremely low birth rate, and
  low death rate
• Rate of natural increase is negative, and life
  expectancy is high

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Stage Five Continued

• The population is falling due to fertility
  decline, emigration and, particularly in Russia,
  increased male mortality.
• The death rate is sometimes due to "diseases of
  wealth", such as obesity or diabetes, leading to
  a gradual fall in population in addition to above
  aging.
• Modern Examples The United Kingdom, Germany, and
  Japan

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The Epidemiological Transition Model
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Stage I Pestilence and Famine

• Infectious and parasite diseases were principle
  causes of death along with accidents and attacks
  by animals and other humans. Thomas Malthus
  called these caused of death natural checks
• Most violent Stage I epidemic was the Black
  Plague(bubonic plague or black death) probably
  transferred to humans by fleas from infected rats

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Stage II Receding Pandemics

• Improved sanitation, nutrition, and medicine
  during the Industrial Revolution reduced the
  spread of infectious diseases.
• Death rates did not improve immediately and
  universally during the early years of the
  Industrial Revolution.
• Poor people who crowded into Industrial Cities
  had high death rates due to Cholera

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Stage III Degenerative Diseases

• Associated with the chronic diseases of aging
• Heart disease and cancer
• Sub-Saharan Africa and South Asia have low
  incidences of cancer primarily because of low
  life expectancy.

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Stage IV Delayed Degenerative

• Life expectancy of older people is extended
  through medical advances.
• Cancer medicines, bypass surgery, better diet,
  reduced use of tobacco, and alcohol
• However, consumption of non-nutritious food and
  sedentary behavior have resulted in an increase
  in obesity in this stage.

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Stage V Return of Infectious Disease

• Return of Stage I diseases (Malaria, SARS, TB,
  AIDS)
• Caused by
• Travel
• Poverty
• Evolution of microbes

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The Demographic and Epidemiological Transition
Models