OECD in the context of "List of cities by GDP"

Gross domestic product (GDP) is a monetary measure of the total market value of all the final goods and services produced and rendered in a specific time period by a country or countries. GDP is often used to measure the economic activity of a country or region. The major components of GDP are consumption, government spending, net exports (exports minus imports), and investment. Changing any of these factors can increase the size of the economy. For example, population growth through mass immigration can raise consumption and demand for public services, thereby contributing to GDP growth. However, GDP is not a measure of overall standard of living or well-being, as it does not account for how income is distributed among the population. A country may rank high in GDP but still experience jobless growth depending on its planned economic structure and strategies. Dividing total GDP by the population gives an idealized rough measure of GDP per capita. Several national and international economic organizations, such as the OECD and the International Monetary Fund, maintain their own definitions of GDP.

GDP is often used as a metric for international comparisons as well as a broad measure of economic progress. It serves as a statistical indicator of national development and progress. Total GDP can also be broken down into the contribution of each industry or sector of the economy. Nominal GDP is useful when comparing national economies on the international market using current exchange rate. To compare economies over time inflation can be adjusted by comparing real instead of nominal values. For cross-country comparisons, GDP figures are often adjusted for differences in the cost of living using purchasing power parity (PPP). GDP per capita at purchasing power parity can be useful for comparing living standards between nations.

Although for many decades, it was customary to focus on GDP and other measures of national income, there has been growing interest in developing broad measures of economic well-being. National and international approaches include the Beyond GDP programme developed by the European Union, the Better Lives Compendium of Indicators developed by the OECD, as well as many alternative metrics of wellbeing or happiness. One of the earliest attempts to develop such an index at national level was Bhutan's Gross National Happiness Index and there are a now a number of similar projects ongoing around the world, including a project to develop for the UK an assessment of national well-being, commissioned by the Prime Minister David Cameron and led by the Office for National Statistics.

Purchasing power parity (PPP) is a measure of the price of specific goods in different countries and is used to compare the absolute purchasing power of the countries' currencies. PPP is effectively the ratio of the price of a market basket at one location divided by the price of the basket of goods at a different location. The PPP inflation and exchange rate may differ from the market exchange rate because of tariffs, and other transaction costs.

The purchasing power parity indicator can be used to compare economies regarding their gross domestic product (GDP), labour productivity and actual individual consumption, and in some cases to analyse price convergence and to compare the cost of living between places. The calculation of the PPP, according to the OECD, is made through a basket of goods that contains a "final product list [that] covers around 3,000 consumer goods and services, 30 occupations in government, 200 types of equipment goods and about 15 construction projects".

Turin (/tjʊəˈrɪn, ˈtjʊərɪn/ ture-IN, TURE-in, Piedmontese: [tyˈriŋ] ; Italian: Torino [toˈriːno] ; Latin: Augusta Taurinorum, then Taurinum) is a city and an important business and cultural centre in northern Italy. It is the capital city of the Piedmont region and of the Metropolitan City of Turin. From 1861 to 1865, it was the first capital of the Kingdom of Italy. The city is mainly on the western bank of the River Po, below its Susa Valley, and is surrounded by the western Alpine arch and Superga hill. The population of the city proper is 856,745 as of 2025, while the population of the urban area is estimated by Eurostat to be 1.7 million inhabitants. The Turin metropolitan area is estimated by the OECD to have a population of 2.2 million.

The city was historically a major European political centre. From 1563, it was the capital of the Duchy of Savoy, then of the Kingdom of Sardinia ruled by the House of Savoy, and the first capital of the Kingdom of Italy from 1861 to 1865. Turin is sometimes called "the cradle of Italian liberty" for having been the political and intellectual centre of the Risorgimento that led to the unification of Italy, as well as the birthplace of notable individuals who contributed to it, such as Camillo Benso, Count of Cavour.

Japan has a highly developed mixed economy, often referred to as an East Asian model. According to the IMF forecast for 2025, it will be the fourth-largest economy in the world by nominal GDP and the fifth-largest by purchasing power parity (PPP) by the end of the year. It constituted 3.7% of the world's economy on a nominal basis in 2024. According to the same forecast, the country's nominal per capita GDP (PPP) will be $56,440 (2025). Due to a volatile currency exchange rate, Japan's nominal GDP as measured in American dollars fluctuates sharply.

A founding member of the G7 and an early member of the OECD, Japan was the first country in Asia to achieve developed country status. In 2024, Japan was the sixth-largest in the world as an importer and eight-largest as an exporter. The country also has the world's fourth-largest consumer market. Japan used to run a considerable trade surplus, but the decline of the manufacturing sector since the 1980s and increased fossil fuel imports after the Fukushima nuclear accident in 2011 have changed this trend in recent years. Being the world's largest creditor nation, Japan has a considerable net international investment surplus. The country has the world's second-largest foreign-exchange reserves, worth $1.4 trillion. Japan has the third-largest financial assets in the world, valued at $12 trillion, or 8.6% of the global GDP total as of 2020. Japan has a highly efficient and strong social security system, which comprises roughly 23.5% of GDP. The Tokyo Stock Exchange is the world's fourth-largest stock exchange by market capitalisation as of 2025.

South Korea has a highly developed mixed economy. By nominal GDP, the economy was worth ₩2.61 quadrillion (US$1.87 trillion). It has the 4th largest economy in Asia and the 13th largest in the world as of 2025. South Korea is notable for its rapid economic development from an underdeveloped nation to a developed, high-income country in a few decades. This economic growth has been described as the Miracle on the Han River, which has allowed it to join the OECD and the G20. It is included in the group of Next Eleven countries as having the potential to play a dominant role in the global economy by the middle of the 21st century. Among OECD members, South Korea has a highly efficient and strong social security system; social expenditure stood at roughly 15.5% of GDP. South Korea spends around 4.93% of GDP on advanced research and development across various sectors of the economy.

South Korea's education system and the establishment of a motivated and educated populace were largely responsible for spurring the country's high technology boom and economic development. South Korea began to adapt an export-oriented economic strategy in the 1960s to fuel its economy. In 2022, South Korea was the ninth largest exporter and ninth largest importer in the world. The Bank of Korea and the Korea Development Institute periodically release major economic indicators and economic trends of the economy of South Korea.

Japan is a great power and a member of numerous international organizations, including the United Nations (since 1956), the OECD, and the Group of Seven. Although it has renounced its right to declare war, the country maintains Self-Defense Forces that rank as one of the world's strongest militaries. After World War II, Japan experienced record growth in an economic miracle, becoming the second-largest economy in the world by 1990. As of 2021, the country's economy is the third-largest by nominal GDP and the fourth-largest by PPP.

Japan has close economic and military relations with the United States, with which it maintains a security alliance. The United States is a major market for Japanese exports and a major source of Japanese imports, and is committed to defending the country, with military bases in Japan.