The following calculation is used to compute the above-mentioned JBLI:
- Sub-indices of the official inflations rates (Belgian Harmonised Index of Consumer Prices and Luxembourgish Consumer Price Index) are aggregated together using a weighting of approximately 80:20 according to how many staff members are based in Belgium and in Luxembourg.
- The sub-indices are then aggregated together using expenditure structures (share of the total expenditure that can be attributed to each sub-index) for staff families working in Brussels.
In order to review the share of expenditure associated to each sub-index, Eurostat is launching this week a Family Budget Survey for staff working in Brussels. Even though, the JBLI also reflects the inflation in Luxembourg and is relevant for staff working in Luxembourg, the latter will not be asked to fill in the survey. The reason for this is that no correction coefficient is foreseen for Luxembourg. It is not known if and how taking into account the expenditure structure of staff working in Luxembourg would impact the JBLI. However, ESTAT could easily verify this by using published levels of expenditure for housing and their share in the total expenditure in Luxembourg. Only then could we be sure that Luxembourg staff members are not penalised by the method to calculate the overall inflation.