Assumptions and Data Conventions

World Economic Outlook Database

Last Updated: April 17, 2012

This site provides the most frequently requested information from the WEO database consistent with the data published in the World Economic Outlook.

Assumptions

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 February 13-March 12, 2012, 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 $114.71 a barrel in 2012 and $110.00 a barrel in 2013 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 0.7 percent in 2012 and 0.8 percent in 2013; that the three-month euro deposit rate will average 0.8 percent in 2012 and 2013; and that the six-month Japanese yen deposit rate will yield on average 0.6 percent in 2012 and 0.1 percent in 2013. 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 early April 2012.

Data Conventions

Data and projections for 184 economies form the statistical basis for 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 WEO conform broadly to the 1993 version of the System of National Accounts (SNA). The IMF's sector statistical standards—the Balance of Payments Manual, Fifth Edition (BPM5), the Monetary and Financial Statistics Manual (MFSM 2000), and the Government Finance Statistics Manual 2001 (GFSM 2001)—have all been aligned with the 1993 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.

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.

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, 2011/2012) to indicate a fiscal or financial year.
• In the reports, shaded areas indicate IMF staff projections.
• Minor discrepancies between sums of constituent figures and totals shown reflect rounding.
• As in the September 2011 World Economic Outlook, fiscal data for Libya are excluded for 2011 and later due to the uncertain political situation.
• Data for the Syrian Arab Republic are excluded for 2011 and later due to the uncertain political situation.
• As in the September 2011 World Economic Outlook, Sudan's data for 2011 exclude South Sudan after July 9. Projections for 2012 and onward pertain to the current Sudan.
• 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.

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.

For details on the terms and conditions for usage of the WEO database, please refer to the IMF Copyright and Usage website, www.imf.org/external/terms.htm.