Such errors may, e.g., arise if prices are not  BIS Review 67/2006  1  adequately adjusted for changes in quality. Moreover, a zero inflation rate for the Eurosystem as a whole would necessarily entail that if some euro area Member States experienced positive inflation rates, this would have to be compensated by deflation in other euro area Member States.
-  Headline inflation, rather than some core inflation concept is taken into consideration. Oil prices are high largely due to demand effects from countries which at the same moment provide the euro area with low import prices and pressure on wages. Eliminating therefore oil from the price index would risk creating a downward pressure to the true inflationary pressures.