- Economic wealth
The common term developed and developing were the common terms used to describe economic terms of a country.
By 1890, the terms developing was replaced the south and later the third world. By 1990, it was realized that poverty is relative and not absolute. Then the term more economically developed and less economically developed countries were increasingly used.
- Social factors
In the western society, economical development means a growth in wealth. Besides that, other criteria have been suggested. E.G; lower births and deaths, lower infant mortality rate, longer life expectancy, slower population growth.