What is the Demographic Transition Model?

The Demographic Transition Model is one of the main ways we can easily understand how a population will change demographically as countries go through economic and social change. It was originally developed in the mid twentieth century as there were similar observations of growth patterns in countries as their economies developed. It was originally designed with 4 stages and has had a fifth added with some people thinking their will be a sixth. It is an evolving model based on observations.
Though the Demographic Transition model is comprised of 5 stages there are currently no countries in stage 1 or 5. The change in stage and population is the result of changing relationships between Birth Rate and Death Rate as shown in the Demographic Transition Model.
Stage 1: The Birth rate and Death Rate are high with low total population Stage 2: The Death Rate starts to fall but Birth Rate remains the same, so we get rapid population growthStage 3: Birth Rate Starts to fall and Death Rate continues to fall. Population Growth falls as the stage continues towards stage 4. Stage 4: When Birth rate and Death Rate begin to level off Stage 5: Death Rate begins to outstrip Birth Rate