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The Demographic Transition Model  

The Demographic Transition Model is a model that proposes how populations should change over time in terms of their birth rates, death rates and total population size.  It is based on demographic data from the UK, and is shown below. 

Image © Rob Gamesby @ http://www.coolgeography.co.uk

It originally consisted of 4 stages, and a fifth stage has been added. 

In stage 1 both the birth rate and death rates are high and fluctuating.  When death rate goes above birth rate the areas population will decrease, while if birth rate goes above death rate the population will increase.  Over extended periods of time this means that population size will change only slightly, with periodic fluctuations up and down.  Reasons for high births rates include little birth control or family planning, children are needed to work and support elderly parents and replacement rate (parents have lots of children to compensate for high infant mortality). Death rates are high due to disease and plague (such as bubonic plague in the British Isles in 1348), inadequate and uncertain food supplies resulting in famine, poor hygiene and sanitation.

In stage 2 the Birth rates stay high throughout because in the UK improvements in society affected death rate first.  The Death rate on the model falls due to such reasons as improved medical care and vaccinations were invented (Edward Jenner invented the first vaccination in 1789 for smallpox in the UK, within 3 months 100,000 people had been vaccinated. In 1954, Becton, Dickinson and Company created the first mass-produced disposable syringe and needle, produced in glass. It was developed for Dr. Jonas Salk's mass administration of one million American children with the new Salk polio vaccine).  Improvements in food production, quality and reliability also contribute to falling death rates; in the UK this can be linked to the Agricultural or Agrarian Revolution.  Improved sanitation and transport of food stuffs, and a decrease in child mortality also contribute to these falling death rates.  Countries at this stage have rapidly growing populations, which China had before its drastic one child policy.

In stage 3 birth rates finally begin to fall and become almost on a par with death rates.  Birth rates fall for many reasons.  Family planning programs, as initiated by governments can have a major impact (see how Britain influences its birth rate)  as can falling infant mortality rates which mean parents recognise that they no longer have to have lots of children as many survive.  In addition, increased material desires mean people want less children so that they can have more consumer goods, and the emancipation of women were women are free to follow careers and put off having a family can have an impact.  This has been evident in the UK were a long history of feminism has changed women’s role in society.  The battle for Suffrage throughout the 19th century finally meant that an act was passed (The Representation of the People Act) which gave the vote to women over 30 who "occupied premises of a yearly value of not less than £5".  Women’s status increased again after WW2 when they had proved themselves more than capable of doing “man’s work”.  This has resulted in an ever free female society, so much so that the average of woman giving birth for the first time in the UK in 2008 was 29 (National Statistics Online).  This is highly variable around the world, as you can see here.  This stage is known as late expanding.

In stage 4 both death rates and birth rates remain low and fluctuate, giving a steady population.  This is typical of many countries that are well developed and is known as the Low fluctuating stage.  Many of the reasons for low birth and death rates are included in the information about stages 2 and 3

Britain's Demographic transition

A final stage has been added to the model, based upon recent countries experiences.  Some countries are now actually experiencing population decline, as birth rates and fertility rates fall below the replacement rate.  This, coupled with increases in life expectancy has resulted in ageing populations for many countries.  A case study of consequences for the UK can be found here.


This model has various strengths and weaknesses, shown in the table below;



It is a great model for anyone living in the UK as it is based upon the UK and we can relate this directly to our country!

Other developed countries such as Japan and France have followed almost exactly the same demographic pattern.

It is simple to understand, dynamic and changes over time, so can be adjusted for future changes.

NICs have followed a similar pattern, BUT have progressed through the model at a faster rate than the British Isles.

Many countries simply have not moved from stage one, despite other changes occurring in their countries.  The model is based upon Western “industrial” economies.  It doesn’t work as well for countries that have not followed this pattern of development.

The importation of technology (e.g. vaccinations) means that death rates can fall much more rapidly than has been observed in Europe.

Governments have acted upon population data and brought about much swifter change to their population, as evidenced in China with its one child policy and in Mauritius with its family planning program.

Some countries actually GO BACK stages on the model in real life!  In the Zimbabwe case study huge strides had been made but under Robert Mugabe over the past 2 decades Zimbabwe has slipped back due to famine, internal strife and HIV and AIDS.

Think about it!

Try the annotation exercise below

Research more HISTORICAL reasons for Britain's changing Birth and Death rates



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