International Comparisons of GDP: Issues of theory and practice

Ian Castles & David Henderson

Published: March 2005

When it comes to making international comparisons of real GDP, different views, conventions and practices are still in evidence. The authors set out the case for using purchasing power parity (PPP) converters for this purpose, rather than conversions based on exchange rates, and give reasons for rejecting various arguments that are still widely made to the contrary. In doing so, they provide instances of the differing current practices of international agencies, and argue the case for greater uniformity and consistency on their part. They make a number of suggestions, general and specific, for improving the quality and presentation of cross-country comparative data.