I suggest that the description of countries as 'developing' or 'developed' should be used with caution — or not at all — in the scientific literature. These categorizations are largely subjective, as shown by their controversial and inconsistent usage among global organizations, which have to navigate substantial geopolitical and cultural shifts.
Bodies such as the United Nations, the International Monetary Fund, the Organization for Economic Co-operation and Development and the World Bank classify countries according to their own criteria. Consequently, the number of nations listed as 'developing' by these agencies varies from 184 (go.nature.com/2hkunbv) to 152 (go.nature.com/2ygmatu), 169 (go.nature.com/2yuxd8k) and down to 47 (go.nature.com/2g8tjdv), respectively.
Indices to justify the division — such as education, life expectancy, infant mortality, public health, personal income and poverty levels — can vary within countries and between them, irrespective of their 'development' status. As the UN and its agencies strive to agree on terminology with representatives of more than 190 countries, we would do well to remember that the designations 'developed', 'less developed' and 'developing' can be used for statistical convenience — but do not reflect a consistent judgement about a country's developmental status.