*  *  *  Ladies and Gentlemen, I have the pleasure of welcoming you to our conference on “Real-Time Data and Monetary Policy” which has been organised by Heinz Herrmann, Athanasios Orphanides and Pierre Siklos. Our conference concentrates on the uncertainty about the actual level of key macro variables.
Until a few years ago, this issue received little attention in the academic debate on monetary policy. This has changed dramatically over the last few years, not least under the influence of economists attending this conference like Athanasios Orphanides or Dean Croushore. Awareness of the measurement problems in real-time data has important consequences.