UN definition of developed or developing country

Most of the countries are divided in three sections

1- Least developed countries
2- Developing countries
3- Developed countries
4- Countries in transition (but these are mainly developing countries of east Europe and some of the developed countries dominating UN can not afford to regard these countries as developing because of similar civilization)

But there is a unsettled debate about the criteria to be used to designate a country under any of these groups. UN, officially, does not give any definition for developed or developing countries. UN website says

"The designations "developed" and developing" are intended for statistical convenience and do not necessarily express a judgement about the stage reached by a particular country or area in the development process"

Main criteria that has been used in the 20th century is the economic development. It is assumed that a country having high GDP per capita is a developed country. Though it is not always true and the high income might not be good enough to survive if the cost of living and inflation are too high. This criteria does not measure holistic development of the society and the individuals. Dr. Amartya Sen has expressed his vies in his book "Development as Freedom". He considers that the freedom is the only measurement of development.

UN is recently moving to accept 'Human Development Index' as new criteria. Bhutan has implemented its own HDI index to measure the development of its citizens.