models

• what does DTM stand for?

  demographic transition model
• what is a model?

  a model provides a structure which is representative of the characteristics, processes and relationships that occur in the real world.
• what does the demographic transition model do?

  it traces a change from high birth rates and high death rates to low birth rates and death rates as a country develops from a pre industrialized economy to an industrialized economic system
• how many stages are in the demographic transition model?

  Thompson's model originally had 4 stages but in recent years a fifth stage has been added to the original model to account for those countries with declining population numbers.
• what is stage 1 of the UK's DTM?

  prior to agricultural and industrial revolutions, birth rates high and families large. birth rates cancelled out by high fluctuating death rates from famines and disease epidemics. infant mortality high so pop size remained stable.
• what is stage 2 of the UK's DTM?

  fall in death rates caused by improved food supply, improved sanitation and hygiene, impact of disease reduced. birth rates remained high due to a lack of contraceptive methods, infant and child mortality persisted, children were seen as an asset, and workers to help care for parents in old age.
• what is stage 3 in the uk's DTM?

  continued fall in death rates due to medical advances, rise in living standards. fall in birth rates due to employment and education legislation, economic and social changes, growth of new ideas.
• what is stage 4 in the UK's DTM?

  death rates start to level out at a low due to national health service. birth rates continue to fall to a similar low level due to increased availability of contraceptives, equal opportunities, social change
• what is the lees model?

  takes a simple push/pull migration model and introduces the ideas of perceptions and intervening obstacles