Seeing into the future is always difficult. But in the world of macroeconomics, just trying to look at the past can be a challenge. Official estimates of economic growth in the UK are regularly revised, so forecasts for growth over the next year have to be made on the basis of an ever-changing report card for the previous year. This post tackles some of the most common questions about UK GDP revisions, a topic close to the heart of many users of the UK’s National Accounts. Are the initial estimates of growth biased? Can you predict revisions? Does UK data get revised more than other countries? And which parts of early estimates of GDP should be approached with caution?