  Appropriate adjustment is made for the influence of exchange rates, price levels and consumption tastes across countries. When these conditions are not met, those performing the comparison may attempt to “standardise” the data themselves. The nature of these adjustments and their levels of transparency can add further confusion to international comparisons2.
For example, New Zealand does not currently produce all of the key macroeconomic statistics that most other advanced economies do3. As a result organisations such as the OECD sometimes attempt to estimate these in order to include New Zealand in international comparisons. 1.