Fifty years of revisions in the official estimates of GDP for the UK and their impact on the interpretation of postwar economic performance

"The value of GDP for the UK has been reported in official reports since World War II.1 Over that time there have been changes in the observations for particular years because of a variety of reasons. The most obvious is that real GDP is regularly revised to reflect the most recent price level. Others include new data, new techniques such as chain-linking, and changes in the definition of what is GDP such as what happens when the UK converted to the European System of Accounts (ESA). Eight years ago, Bill Martin published an article in the Financial Times that was critical of the ONS numbers before 1987. He attributed the cause the 1998 conversion to the ESA(95) In another article he suggested that these numbers could be fixed, but recent events would seem to show his advise has not been followed. We do not propose in this paper to explain the changes in the various versions of annual GDP, the quality of them, or why one is preferred to another. This paper does three things. First, it reports on the compiling of all the official versions of GDP that have been published since 1959 that is now available online. The second part of the paper presents a discussion of what was the impact these numbers had when they were published and if subsequent revisions would have changed the conclusions made at the time. Finally we will discuss the large revisions of last two years and the implication for the current interpretation of post war growth."