Lessons > The Demographic Transition > Step 1
At the most basic level, the increase or decrease in population can be calculated by following the simple formula:
BIRTH RATE - DEATH RATE + IMMIGRATION = GROWTH RATE
(See Unit 5 text for a more extensive explanation.) Please note that our model does not take immigration into account, so we are looking at birth and death rates only.
Birth and death rates are expressed in a number of different ways. Overall rates are often expressed as the number of births per woman over her whole life, and deaths per year. But for use in predicting population growth, population models use birth and death rates specific to each age group, over a step of 5 years. In this simulator, the overall rates are shown on buttons in the grey box. When you click the buttons, a detail dialog shows the age group specific rates.
To get a sense of the demographic transition continuum, start by running the simulator to 2050 for all nine countries (click on Run button). Record their population growth rates at the end of the simulated period in the Data Table and number the countries by growth rate from highest (earliest in the demographic transition) to lowest (farthest along the transition). Then answer the following questions.