Certain types of social and economic changes are known to have demographic implications.
The demographic transition experienced by the developed countries and currently being experienced by some of the developing countries indicate that the high birth and death rates gave way to low birth and death rates after they passed through the stage of declining death rates and high birth rates and then the stage of declining birth and death rates.
This transition has accompanied development in the social and economic sphere. The large family system in the West was replaced by the small family system following the impact of industrialisation and urbanisation.
When society changed from an agrarian rural economic base to an industrial urban economic base, it was soon evident that it was not advantageous to have large families; gradually, therefore, the small family replaced the large family.
Higher aspirations and expectations arising out of higher levels of economic and social development tended to influence people in favour of having smaller families.
In recent times, Japan has provided a striking example of a country that has completed the demographic transition. From a stage of high birth and death rates, it has now achieved the stage of low birth and death rates, which has led to a small population growth.
This was achieved through such demographic measures as postponement of marriage, acceptance of contraception and sterilisation, utilisation of abortion and adoption of migration to other countries.
The non-demographic measures were stepping up industrial productivity, increasing food supply and generally raising the standard of living.