World Economic Outlook Database - Groups and Aggregates Information

World Economic Outlook

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The World Economic Outlook (WEO) divides the world into two major groups: advanced economies and emerging and developing economies.
The classification is not based on strict criteria, economic or otherwise, and has evolved over time.
The objective of the classification is to facilitate analysis by providing a reasonably meaningful method of organizing data.
Some economies remain outside the classification and therefore are not included in the analysis; Cuba and the Democratic People’s Republic of Korea are cited as examples of economies that are not IMF members and therefore not monitored by the IMF.
Last Updated: April 2025

Composite data for country groups in the WEO are either sums or weighted averages of data for individual countries.
Arithmetically weighted averages are used for all data for the emerging market and developing economies group—except data on inflation, for which geometric averages are used.
Unless noted otherwise, group composites are computed if 90 percent or more of the share of group weights is represented.

Domestic economy indicators (growth rates or ratios): weighted by GDP valued at purchasing power parity as a share of total world or group GDP.
Inflation:
- For advanced economies (and subgroups): annual rates are simple percentage changes from the previous years.
- For world inflation and inflation in emerging market and developing economies (and subgroups): annual rates are based on logarithmic differences.
Real GDP per capita in purchasing-power-parity terms: composites are sums of individual country data after conversion to the international dollar in the years indicated.
Euro area sector composites: unless noted otherwise, composites for all sectors for the euro area are corrected for reporting discrepancies in transactions within the area.
Annual GDP reporting:
- Unadjusted annual GDP data are used for the euro area and for the majority of individual countries.
- Cyprus, Ireland, Portugal, and Spain report calendar-adjusted data.
- For data prior to 1999, data aggregations apply 1995 European currency unit exchange rates.

Fiscal data composites: sums of individual country data after conversion to US dollars at the average market exchange rates in the years indicated.
Unemployment rates and employment growth composites: weighted by labor force as a share of group labor force.
External sector statistics:
- Balance of payments data: sums after conversion to US dollars at the average market exchange rates in the years indicated.
- Debt denominated in currencies other than US dollars: sums after conversion to US dollars at end-of-year market exchange rates.
Foreign trade volumes and prices: arithmetic averages of percent changes for individual countries weighted by the US dollar value of exports or imports as a share of total world or group exports or imports (in the preceding year).

Users should expect different aggregation methods depending on the statistic:
- Sums for many levels of nominal aggregates (converted at specified exchange rates).
- GDP-weighted PPP shares for domestic-economy ratios and growth rates.
- Geometric vs arithmetic vs logarithmic methods for different inflation aggregates.
Coverage rules (90 percent threshold) mean some group composites may not be computed if country coverage falls below that threshold.
Historical aggregation of European data applies specific exchange-rate conventions for pre-1999 data (1995 ECU exchange rates) and recognizes calendar-adjusted reporting for certain countries.