Reliable and timely economic data are essential for policymakers. A cursory glance at the Budget documents from HM Treasury or the different monetary policy publications from the Bank of England reveals the direct and immediate use of a wide range of macroeconomic data for policy. Those fiscal and monetary policy decisions, in turn, impact on every household and business and therefore policy that is based on inaccurate statistics is costly to people in Britain.
In this paper we estimate the macroeconomic impact of revisions to official national accounts data. We examine this question through the prism of monetary policy and restrict our focus to two episodes when the ONS introduced sizeable revisions to its preliminary GDP data. The first episode relates to the period around the Asian Financial Crisis when early quarterly GDP growth estimates were subsequently revised higher. The second episode covers the Global Financial Crisis and in this case the early estimates of real GDP were later revised lower.