Assumptions and Data Conventions

World Economic Outlook Database

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 will remain constant at their average levels during January 30 to February 27, 2008, except for the currencies participating in the European exchange rate mechanism II (ERM II), which are assumed to remain constant in nominal terms relative to the euro; that established policies of national authorities will be maintained; that the average price of oil will be $95.50 a barrel in 2008 and $94.50 a barrel in 2009, and 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 3.1 percent in 2008 and 3.4 percent in 2009; that the three-month euro deposits rate will average 4.0 percent in 2008 and 3.6 percent in 2009; and that the six-month Japanese yen deposit rate will yield an average of 1.0 percent in 2008 and of 0.8 percent in 2009. 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 end-March 2008.

Data Conventions

In line with recent improvements in standards of reporting economic statistics, several countries have phased out their traditional fixed-base-year method of calculating real macroeconomic variables levels and growth by switching to a chain-weighted method of computing aggregate growth. Recent dramatic changes in the structure of these economies have obliged these countries to revise the way in which they measure real GDP levels and growth. Switching to the chain-weighted method of computing aggregate growth, which uses current price information, allows countries to measure GDP growth more accurately by eliminating upward biases in new data. Currently, real macroeconomic data for Albania, Australia, Austria, Azerbaijan, Belgium, Canada, Cyprus, Czech Republic, Denmark, euro area, Finland, Georgia, Germany, Greece, Iceland, Ireland, Italy, Japan, Kazakhstan, Lithuania, Luxembourg, Malta, the Netherlands, New Zealand, Norway, Poland, Portugal, Russia, Slovenia, Spain, Sweden, Switzerland, the United Kingdom, and the United States are based on chain-weighted methodology. However, data before 1996 (Albania), 1988 (Austria), 1994 (Azerbaijan), 1995 (Belgium), 1995 (Cyprus), 1995 (Czech Republic), 1995 (euro area), 1996 (Georgia), 1991 (Germany), 2000 (Greece), 1990 (Iceland), 1995 (Ireland), 1994 (Japan), 1994 (Kazakhstan), 1995 (Luxembourg), 2000 (Malta), 1987 (New Zealand), 1995 (Poland), 1995 (Russia), 1995 (Slovenia), and 1995 (Spain) are based on unrevised national accounts and subject to revision in the future.

All data refer to calendar years, except for the following countries, which refer to fiscal years: Australia (July/June); Egypt (July/June); Haiti (October/September); Islamic Republic of Iran (April/March); Mauritius (July/June); Myanmar (April/March); Nepal (July/June); New Zealand (July/June); Pakistan (July/June); Samoa (July/June); and Tonga (July/June).

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.
• Missing data are indicated by "n/a".
• "--" indicates the data are not zero but negligible.
• Blank row means that data are not available or not applicable.
• "/" means between years or months (for example, 2005/2006) to indicate a fiscal or financial year.
• In the reports, shaded areas indicate IMF staff projections.