The first releases of official statistics are often revised in subsequent releases, sometimes substantially. Such revisions can impact on policy decisions, as revisions to first published data may alter the previous assessment of the state of the economy. This may occur through a changed interpretation based on the revised data itself or the impact the revision may have on econometric models which may incorporate several statistics, each subject to revision. Whilst this is a recognised issue of key importance, most producers of official statistics do not quantify expected revisions to their data and economists do not have the required data to test the sensitivity of their econometric models to revisions in input data. This important gap in knowledge required to effectively use official statistics, and demands from central banks motivated the OECD to develop a unique new product: the Main Economic Indicators Original Release Data and Revisions Database, now freely available at: http://stats.oecd.org/mei/default.asp?rev=1 . Accessing this source of originally published data will enable analysts to test the likely effectiveness of econometric models in simulated real-time. It will also enable producers of official statistics to study the magnitude and direction of subsequent revisions to published data which can lead to a better understanding of the statistical compilation process, enabling problems to be identified and improvements to be made. Revisions analysis also provides important information to users on the robustness of first estimates...