Ian Castles is Visiting Fellow in the Crawford School of Economics and Government at the ANU and was a former Commonwealth Statistician. He writes on East Asia Forum::
In his review of the Australian Government’s defence white paper, Greg Sheridan, Foreign Editor of The Australian, says, ‘just for the record’, that the US economy is six times as big as China’s. He claims that the white paper’s assertion that China has the potential to overtake the US as the world’s largest economy by 2020 is ‘silly’ (‘A battle of words’, Weekend Australian, 2-3 May, p. 22).
Sheridan also claims that the use of the purchasing power parity (PPP) method to compare the relative size of economies is ‘sleight of hand’ which gives rise to a ‘statistical illusion’ and ‘a meaningless measure’.
He is wrong on all counts. Even on the discredited ‘market’ exchange rate method that he persistently champions against the unanimous advice of economic statisticians and index number theorists, the GDP of the US is now only three times as big as China’s, not six times as big (IMF, World Economic Outlook Database, April 2009).
