The most common index for measuring developments is

The most common index for measuring developments is the per capita income. This index is used to measure the economic development of a country or region by dividing the total income of that area by its total population. It provides a measure of the average income per person and is widely used as an indicator of a country's standard of living and economic growth. By looking at the per capita income, policymakers can make informed decisions about economic policies and development programs.