he theory gives an explicit relationship between population growth and economic advancement. The theory states that there are some natural and manmade forces (technological advancement), which will tend to bring about relief in the size structure, density and geographical distribution of the population with the view to exerting a stable population growth at any particular point in time.
The theory explains that as a country advances economically, it passes through some stages of population growth.
The stage one which is the PRE- MODERN stage which is characterized by high fertility and high mortality. At this stage, there has not been any sufficient or technological advancement whatsoever.
The stage two which EARLY TRANSITION stage is characterized by high birth rate and low death rate. This was the beginning of the demographic transition theory. It was a period of slow growing population to rapidly increasing population.
The stage three, which is the LATE TRANSITION stage, was a period characterized by modern technological advancement in all aspect of human life. At this stage, fertility started declining and there was low death rate and birth rate owing to the improvements in the economic and social life of the people.