3.0 2.5 2.0 1.5 1.0 0.5 0.0 -0.5  11  12  13  14  15  16  17  18  19  CPIF Sources: Statistics Sweden and the Riksbank  A simple way of getting rid of the white noise and clarifying the actual trend is to calculate a twelve-month moving average for the series. 14 Figure 3 shows the results of such a calculation. Now the white noise has been removed and the underlying development is shown more clearly. But it must be emphasised that this is the underlying development given the method I have chosen. 14 First I have calculated the level for a twelve-month moving average for the CPIF. Then I have calculated the twelve-month change for the moving average. 6 [19]  Figure 3. CPIF inflation, twelve-month moving average Annual percentage change. 3.0 2.5 2.0 1.5 1.0 0.5 0.0 -0.5  11  12  13  14  15  16  17  18  19  CPIF, twelve-month moving average Sources: Statistics Sweden and the Riksbank  The second common method of calculating underlying inflation is, as we said, to exclude certain predetermined prices or groups of prices. Perhaps the most common measure used internationally is inflation excluding energy and food prices. Energy prices contribute to more temporary and short-term price movements, the same applies to food prices. One reason for these price movements is temporary variations in demand. Unusual weather can also temporarily affect prices of, for instance, electricity, cereals, fruit and vegetables.
The new method, where one follows the prices on a top list for books sold, probably gives greater variations than the old method where one followed the prices on a number of indicator books. The top list changes every month, while the indicator list changed less often. Sales are now captured to a greater extent than before. 27 Foreign air travel was not included in Table 1, but a new method of measuring prices has contributed to a new seasonal pattern with a higher volatility in recent years. 14 [19]  Underlying measures and actual monetary policy The different measures of underlying inflation give us the opportunity to approach the existing data and view it from different angles. But in the next step, the measures will be used by policymakers responsible for monetary policy. Here a conflict arises between on the one hand bringing forward various underlying measures and on the other hand being clear and transparent about the objective of monetary policy. The conflict become particularly clear if one chooses to use measures of underlying inflation that systematically deviate from the actual rate of inflation. Or, in other words, the poorer the measure of underlying measure of inflation, the greater the communication challenges. I would say that we have seen clear examples of this conflict in recent years: In June 2018, analysts at Handelsbanken Capital Markets considered it necessary to deny that the Riksbank had changed its target variable in a newsletter.