Assumptions and Data Conventions
World Economic Outlook DatabaseLast Updated: October 08, 2013
The World Economic Outlook (WEO) database contains selected macroeconomic data series from the statistical appendix of the World Economic Outlook report, which presents the IMF staff's analysis and projections of economic developments at the global level, in major country groups and in many individual countries. The WEO is released in April and September/October each year.
This site provides the most frequently requested information from the WEO database consistent with the data published in the World Economic Outlook.
A number of assumptions have been adopted for the projections presented in the World Economic Outlook. It has been assumed that real effective exchange rates remained constant at their average levels during July 29-August 26, 2013, except for the currencies participating in the European exchange rate mechanism II (ERM II), which are assumed to have remained constant in nominal terms relative to the euro; that established policies of national authorities will be maintained (for specific assumptions about fiscal and monetary policies for selected economies, see Box A1); that the average price of oil will be $104.49 a barrel in 2013 and $101.35 a barrel in 2014 and will remain unchanged in real terms over the medium term; that the six-month London interbank offered rate (LIBOR) on U.S. dollar deposits will average 0.4 percent in 2013 and 0.6 percent in 2014; that the three-month euro deposit rate will average 0.2 percent in 2013 and 0.5 percent in 2014; and that the six-month Japanese yen deposit rate will yield on average 0.2 percent in 2013 and 0.3 percent in 2014. These are, of course, working hypotheses rather than forecasts, and the uncertainties surrounding them add to the margin of error that would in any event be involved in the projections. The estimates and projections are based on statistical information available through September 23, 2013.
Data and projections for 189 economies form the statistical basis of the World Economic Outlook (the WEO database). The data are maintained jointly by the IMF’s Research Department and regional departments, with the latter regularly updating country projections based on consistent global assumptions.
Although national statistical agencies are the ultimate providers of historical data and definitions, international organizations are also involved in statistical issues, with the objective of harmonizing methodologies for the compilation of national statistics, including analytical frameworks, concepts, definitions, classifications, and valuation procedures used in the production of economic statistics. The WEO database reflects information from both national source agencies and international organizations.
Most countries’ macroeconomic data presented in the World Economic Outlook conform broadly to the 1993 version of the System of National Accounts (SNA). The IMF’s sector statistical standards—the Balance of Payments and International Investment Position Manual, Sixth Edition (BPM6), the Monetary and Financial Statistics Manual (MFSM 2000), and the Government Finance Statistics Manual 2001 (GFSM 2001)—have been or are being aligned with the 2008 SNA. These standards reflect the IMF’s special interest in countries’ external positions, financial sector stability, and public sector fiscal positions. The process of adapting country data to the new standards begins in earnest when the manuals are released. However, full concordance with the manuals is ultimately dependent on the provision by national statistical compilers of revised country data; hence, the World Economic Outlook estimates are only partially adapted to these manuals. Nonetheless, for many countries the impact of conversion to the updated standards will be small on major balances and aggregates. Many other countries have partially adopted the latest standards and will continue implementation over a period of years.
Note: Many other countries are implementing the 2008 SNA and will release national accounts data based on the new standard in 2014. A few countries use versions of the SNA older than 1993. A similar adoption pattern is expected for the BPM6. Although the conceptual standards use the BPM6, the World Economic Outlook will continue to use the BPM5 presentation until a representative number of countries have moved their balance of payments accounts into the BPM6 framework.
Consistent with the recommendations of the 1993 SNA, several countries have phased out their traditional fixed-base-year method of calculating real macroeconomic variable levels and growth by switching to a chain-weighted method of computing aggregate growth. The chain-weighted method frequently updates the weights of price and volume indicators. It allows countries to measure GDP growth more accurately by reducing or eliminating the downward biases in volume series built on index numbers that average volume components using weights from a year in the moderately distant past.
Composite data for country groups in the World Economic Outlook are either sums or weighted averages of data for individual countries. Unless noted otherwise, multiyear averages of growth rates are expressed as compound annual rates of change. Arithmetically weighted averages are used for all data for the emerging market and developing economies group except inflation and money growth, for which geometric averages are used. The following conventions apply.
- Composites for other data relating to the domestic economy, whether growth rates or ratios, are weighted by GDP valued at purchasing power parity (PPP) as a share of total world or group GDP.
- Composites for data relating to the domestic economy for the euro area (17 member countries throughout the entire period unless noted otherwise) are aggregates of national source data using GDP weights. Annual data are not adjusted for calendar-day effects. For data prior to 1999, data aggregations apply 1995 European currency unit exchange rates.
- Composites for fiscal data are sums of individual country data after conversion to U.S. dollars at the average market exchange rates in the years indicated.
- Composites unemployment rates are weighted by labor force as a share of group labor force.
- Composites relating to external sector statistics are sums of individual country data after conversion to U.S. dollars at the average market exchange rates in the years indicated for balance of payments data.
- Composites of changes in foreign trade volumes and prices, however, are arithmetic averages of percent changes for individual countries weighted by the U.S. dollar value of exports or imports as a share of total world or group exports or imports (in the preceding year).
- Composite data are provided for various groups of countries organized according to economic characteristics or region. Unless otherwise noted, country group composites represent calculations based on 90 percent or more of the weighted group data.
The following conventions have been used throughout the World Economic outlook:
- Domestic economy series are expressed in billions of national currency units
- External accounts series are expressed in billions of U.S. dollars.
- "Billion" means a thousand million; "trillion" means a thousand billion.
- Missing data are indicated by "n/a".
- Blank row means that data are not available or not applicable.
- "/" means between years or months (for example, 2012/13) to indicate a fiscal or financial year.
- Shading differences are used to distinguish historical results from IMF staff projections.
- Minor discrepancies between sums of constituent figures and totals shown reflect rounding.
- For some countries, the figures for 2012 and earlier are based on estimates rather than actual outturns.
- Data refer to calendar years, except for a few countries that use fiscal years. Please refer to the country information section of the WEO online database for a complete listing of the reference periods for each country.
- As used here, the terms “country” and “economy” do not always refer to a territorial entity that is a state as understood by international law and practice. Some territorial entities included here are not states, although their statistical data are maintained on a separate and independent basis
Further Information and Data
The data appearing in the World Economic Outlook are compiled by the IMF staff at the time of the WEO exercises. The historical data and projections are based on the information gathered by the IMF country desk officers in the context of their missions to IMF member countries and through their ongoing analysis of the evolving situation in each country. Historical data are updated on a continual basis as more information becomes available, and structural breaks in data are often adjusted to produce smooth series with the use of splicing and other techniques. IMF staff estimates continue to serve as proxies for historical series when complete information is unavailable. As a result, WEO data can differ from other sources with official data, including the IMF’s International Financial Statistics.
The WEO data and metadata provided are “as is” and “as available,” and every effort is made to ensure, but not guarantee, their timeliness, accuracy, and completeness. When errors are discovered, there is a concerted effort to correct them as appropriate and feasible. Corrections and revisions made after publication are incorporated into the electronic editions available from the IMF eLibrary (www.elibrary.imf.org) and on the IMF website. All substantive changes are listed in detail in the online tables of contents.
For details on the terms and conditions for usage of the WEO database, please refer to the IMF Copyright and Usage website.