I exclude one country that meets the two criteria: Norway. The OECD series for Norway's potential output is volatile, making it difficult to project the pre-crisis path of potential into the future. This problem may reflect the large share of oil in Norway's output.
The base years for the output series differ across countries, and they differ between the December 2007 and May 2014 Outlooks. For each country, I make the two vintages of data consistent by multiplying the December 2007 series for output and potential output by a ratio: (output in 2000 in the May 2014 data)/(output in 2000 in the December 2007 data).
Each country's weight is proportional to the product of (2015 nominal GDP in dollars) and (Y**/Y). Nominal GDP in dollars is taken from the April 2014 WEO, because the OECD does not report this variable.
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