As from the January index in 2011 (published on 10 February 2011), a new weighting will be applied to the consumer price index based on the national accounts' figures for household consumption. Read article on new source on weighting.
As of July index, published the 10th of August 2006, changes are made in the housing component of the CPI. A new sampling method is established as well as changes in the computation method for estimating changes for actual and imputed rentals for housing.
New sampling method
One of the challenges in creating rental statistics is the lack of existing registers of dwellings for rental as well as of tenants. As of July index 2006, the sample of dwellings for rental is established through selecting addresses from the Central Population Register (DSF). To exclude homeowners from the sample, the addresses are connected to the Ground Property, Address and Building Register (GAB). Finally to reduce the portion of cooperative dwellings, the sample is connected to register data of large cooperative firms.
This sample is the foundation for the Rental Market Survey 2006 as well as the monthly estimations of rental development for actual and imputed rentals for housing in the CPI. The total sample amounts to approx. 5 100 tenants. The computations of the monthly price development will, as of July index, be based on a third of the total sample i.e. 1 700 tenants. A third of the sample will be rolled each month such that tenants participate in the survey every third month. The sample is stratified by geographical areas and by dwelling size, such as number of rooms.
Adjustment of computation method for actual and imputed rentals for housing
As of the July index, the computation method is adjusted. Both actual and imputed rentals for housing are based on actual observed rentals in the rental market. Since the characteristics are quite different in the rental and the owner-occupied market, as of July index, corrections are made to account for these differences by introducing weight shares both for geographical areas and dwelling size such as number of rooms. There will be no breaks in the official time series of actual and imputed rentals for housing, but in detailed levels there are changes due to new stratifications.
New weight foundation for imputed rentals for housing
In August each year the weights in the CPI is updated based on expenditure shares from the Household Budget Survey (HBS). From August 2006 to July 2007, the weights are based on the HBS from 2003, 2004 and 2005. As of August index, to be published on the 11th of September 2006, the Rental Market Survey 2005 will be the foundation for the estimation of expenditure shares of homeowners in the 2005 HBS and the weight shares in the CPI. To achieve the best approximation of owner-occupied housing the sample is restricted to only professionally based rentals, rejecting rentals containing different forms of regulations and subsidies.
The CPI for August 2005 will include an improved sub-index for food and non-alcoholic beverages that solely is based on bar code data. The choice of method and computation for the improved index will be thoroughly documented later. The change will, however, involve some practical adjustments in the CPI.
The purpose of the change in the sub-index is to exploit all the information available to create an improved and more robust index. There will be no breaks from previous series and the official groupings, coicop level 4, 3 and 2, will remain identical. The changes appear on a more detailed level, and the greatest change is that the representative goods in the sub-index disappear completely.
Table 4 will no longer be published
The sub-index for food and non-alcoholic beverages previously consisted of approximately 250 representative goods, of which a large number were published monthly in Table 4 with monthly index figures and average prices for the reference year 1998. As of the August 2005 release the computation of the index based on the 250 representative goods will be replaced by an index based on almost all the prices within the food and non-alcoholic beverages grouping. The bar code data reports contain more than 300 000 price observations for 14 000 goods every month. This information enables an improved and more robust index for food and non-alcoholic beverages.
A consequence of the change is that the indices at the most elementary level no longer will be computed at representative goods level, but at a more aggregated coicop 6 level. As a result, Table 4 will disappear, but an alternative will be considered as soon as the computation process has been implemented.
Read more on adjustments in CPI in the article CPI adjusted for tax changes and excluding energy products (Economic Survey 1/2002).