When John Kennedy was contesting the presidential election against Richard Nixon, he argued that a missile gap had opened between USA and USSR and that indicated the fault of the Republican administration and if elected he would correct the problem. He won the election but it turned out there was no missile gap. It was a made up charge which just seemed plausible.
Numbers are powerful weapons of political rhetoric. The UK has now the Office of Budget Responsibility (OBR) which polices the use of official statistics by the government. The Office of National Statistics (ONS) recently upbraided Prime Minister Cameron for misrepresenting the numbers on unemployment. The OBR checks that the Chancellor does not create an impression of more growth than the numbers justify. Even better has been the contribution of the Bank of England about its inflation forecasts. They are regularly published with their confidence intervals shown explicitly. This ‘fan diagram’ has become a staple of policy debates. A whole generation of politicians has been educated about the penumbra of uncertainty attaching to any and all statistical estimates.
One almost wishes that the Election Commission would do similar policing of the use of statistics during election campaigns. We had the recent example of Narendra Modi contrasting the GDP growth of 8.4% under BJP/NDA and 4.8% under the UPA2 . As numbers go, these are interesting only due to the juxtaposition of the digits 4 and 8. Yet P Chidambaram accused Modi of having ‘a fake encounter’ with statistics. As the dispute escalated, Yashwant Sinha accused Chidambaram of terrorism with statistics. One side accused the other of overstating the GDP growth rate by taking one year and not the five year average. As the UPA average for 2004-09(8.4%) is better than the BJP/NDA for 1998-2004(6%), the argument was that by not stating it Modi had falsified the situation. But the numbers as such were not false; they were just point estimates rather than averages.
Why should there be disputes about numbers which are easily checkable? The number 8.4% was claimed to have been published by UPA1 in its Economic Report for 2003-2004. It was claimed that the number was adjusted upwards from 8.2 to 8.4. Numbers get revised upwards or downwards. Economic statistics are fragile and very hard to define accurately anywhere within the range as small as 0.2 or even 0.5. Recently the US Department of Commerce recalculated all the GNP