The success of the euro area has demonstrated that one size can fit all. Let me briefly mention three pieces of evidence which support this. First, inflation dispersion has declined and has been around 1 percentage point since the second half of 1999. This compares favourable with inflation dispersion across a monetary union of similar size, the US.
This poses a whole set of problems for official price statistics, and it has not yet been possible to solve them all in a fully satisfactory manner. For instance, it is hardly feasible to take due account of new goods and new types of outlets in “real time” when measuring inflation.