PPP conversions are currency conversion rates that both convert to a common currency and equalise the purchasing power of different currencies. 1  OECD (2006). 2  While not stated as an explicit condition for international comparisons, the statistics themselves must have integrity in order to compare with other countries.
The past statistical issues in Greece are a well documented example of statistics which lacked integrity and which made it difficult to draw meaningful comparisons with other countries. 3  See Barrow (2010) and RBNZ (2007).