| Abstract: | The calculation of purchasing power parities and quantity comparisons for a given year provides interesting information about the relative importance of countries. However, it is necessary to make these estimates annually in order to enable users to apply these parities for international comparison of annual data expressed in national currency. The paper deals with the problems related to merging spatial comparisons and temporal volume and price movements for the countries of the European Community. For these countries full information was collected in 1975 and in 1980, whereas in the intermediate years some price data were collected and price indices at a detailed level have also been collected. First the theoretical problems of consistency between the spatial results and temporal indices are discussed. Because no immediate consistency can be obtained, several methods are proposed to achieve consistency, by estimating one unique set of spatial and temporal indices. The available information for the period 1975-80 has been used in order to test the numerical differences between two sets of parities and price indices over time. Besides theoretical reasons for inconsistency, it is also necessary to take into account errors in the price observations or in the price indices. The results presented in the paper should be considered as provisional and further work will be undertaken to obtain better insights into the inconsistency between these sets of data. |
