A number of assumptions have been adopted for the projections presented in the World Economic Outlook 

(WEO). It has been assumed that real effective exchange rates remained constant at their average levels during July 23, 2021, to August 20, 2021, except for those for the currencies participating in the European exchange rate mechanism 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 mon-etary policies for selected economies, see Box A1 in the Statistical Appendix); that the average price of oil will be $65.68 a barrel in 2021 and $64.52 a barrel in 2022 and will remain unchanged in real terms over the medium term; that the six-month London interbank offered rate on US dollar deposits will average 0.2 percent in 2021 and 0.4 percent in 2022; that the three-month euro deposit rate will average –0.5 percent in 2021 and 2022; and that the six-month Japanese yen deposit rate will yield, on average, –0.1 percent in 2021 and 0.0 percent in 2022. 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 27, 2021.