I want understand how gdp are working in economic development
Gross Domestic Product (GDP) is one of the most widely used measures of an economy’s output or production. It is defined as the total value of goods and services produced within a country’s borders in a specific time period — monthly, quarterly or annually.
GDP is an accurate indication of an economy's size, while GDP per capita has a close correlation with the trend in living standards over time, and the GDP growth rate is probably the single best indicator of economic growth. As Nobel laureate Paul A. Samuelson and economist William Nordhaus put it, “While GDP and the rest of the national income accounts may seem to be arcane concepts, they are truly among the great inventions of the twentieth century.”