In a market-based economy, household, producer, and government choices about resource allocation are influenced by relative prices, including the real exchange rate, real wages, real interest rates, and other prices in the economy. Relative prices also largely reflect these agents’ choices. Thus relative prices convey vital information about the interaction of economic agents in an economy and with the rest of the world. For most economies PPP figures are extrapolated from the 2011 International Comparison Program (ICP) benchmark estimates or imputed using a statistical model based on the 2011 ICP. For 47 high- and upper middle-income economies conversion factors are provided by Eurostat and the Organisation for Economic Co-operation and Development (OECD).
Official or market exchange rates are often used to convert economic statistics in local currencies to a common currency in order to make comparisons across countries. Since market rates reflect at best the relative prices of tradable goods, the volume of goods and services that a U.S. dollar buys in the United States may not correspond to what a U.S. dollar converted to another country’s currency at the official exchange rate would buy in that country, particularly when nontradable goods and services account for a significant share of a country’s output. An alternative exchange rate – the purchasing power parity (PPP) conversion factor – is preferred because it reflects differences in price levels for both tradable and nontradable goods and services and therefore provides a more meaningful comparison of real output.
Indicator Name: PPP conversion factor, GDP (LCU per international $)
Indicator Code: PA.NUS.PPP