CSO publication, , 11am
Despite continual changes in consumer tastes and preferences, standard of living, and in the range of goods and services available on the market, household purchasing patterns generally change slowly over time. It is this relative stability in the pattern of household purchases which permits the use of fixed weighting patterns in the compilation of the CPI. However, these index weights must be periodically updated if they are to continue to be representative of current expenditure patterns. Twelve different weighting bases have been used to date in the compilation of the index since the foundation of the State in 1922. The main features of the earlier index series are briefly described below:
This was the first official index of consumer prices compiled for the State. It was introduced in respect of March 1922. The expenditure basis represented the purchasing pattern of working-class families in 1922 as derived from a Household Budget Inquiry conducted in June of that year. This index was compiled quarterly up to August 1947. The weighting basis was scheduled for revision during the late thirties but plans for a Household Budget Inquiry necessary for this purpose had to be postponed because of the abnormal pattern of consumer expenditure during the 1939-45 war years and subsequent period. As an interim measure an updated weighting basis was introduced in August 1947 using alternative data sources.
This second series was titled the Interim Cost of Living Index (Essential Items). It was compiled for each quarter from mid-August 1947 to mid-August 1953. The weighting basis related to the purchasing pattern of non-agricultural employee households. This was estimated from national income and expenditure data combined with the results of the National Nutrition Survey undertaken in 1946. By 1951, consumer expenditure had stabilised to what appeared to be normal post-war patterns and a large-scale urban Household Budget Inquiry was conducted during 1951-52 to provide up-to-date index weights.
This index series was introduced for mid-November 1953 and was compiled each quarter up to and including mid-November 1968. While the interim index related only to non-agricultural employee households, the weighting basis of the new index extended to all urban households. In addition, the coverage of the index was extended to include the full range of consumer goods and services. The former title Cost of Living Index was also changed to the present official title Consumer Price Index to avoid any possible misunderstanding that the index measured changes in the cost of living rather than price changes.
This index series was introduced for mid-February 1969 and was compiled each quarter up to mid-November 1975. The weighting basis related to the expenditure pattern of all urban households as determined from the results of the 1965-66 Household Budget Inquiry. In addition to the introduction of revised weights, a number of other major updating of the index were also undertaken. A revised national panel of retail and service outlets representative of the existing retail structure was selected. Prices were collected on both the old and new basis in two separate inquiries with fifteen days intervening during November 1968.
This index series was introduced for mid-February 1976 and compiled each quarter up to mid-November 1982. The weighting basis of the index was extended to all households in the country (i.e. urban and rural) on the basis of the results of the 1973 national Household Budget Survey. No major change was made to the existing panel of local retail outlets in which these items were priced.
This index series was introduced for mid-February 1983 and was compiled each quarter up to mid-November 1989. The weighting pattern continued to relate to all households in the country based on the results of the 1980 national Household Budget Survey. Other major updatings of the index were also completed. The selection of varieties priced was substantially revised and increased in number from 685 to 722. The selection of local retail outlets in which the prices were surveyed was also extensively overhauled. As with November 1968 updating this necessitated, for continuity purposes, two separate national price collections on the old and new basis, respectively, within fifteen days of each other.
Index with base mid-November 1989 as 100
This index series was introduced for mid-February 1990 and was each quarter up to mid-November 1996. The weighting pattern was based on the results of the 1987 Household Budget Survey. The selection of varieties was reviewed and the number of varieties in the index increased from 722 to 807.
Index with base mid-November 1996 as 100
This index series coincided with the introduction of a monthly CPI. The weighting pattern used in the index was based on the results of the 1994-1995 Household Budget Survey. The selection of varieties was reviewed and their number in the index increased to 985 varieties.
This index series coincided with the changeover to the Euro and the introduction of the EU Classification of Individual Consumption by Purpose Adapted to the Needs of the Harmonised Indices of Consumer Prices (2000) for the main sectoral analysis of the CPI. The weighting pattern used in the index was based on the results of the 1999-2000 Household Budget Survey. The review of item headings resulted in 613 item headings in the CPI basket of goods and services.
This index series was introduced for mid-January 2007. The weighting pattern used in the index was based on the results of the 2004-2005 Household Budget Survey. The review of item headings resulted in 616 item headings in the CPI basket of goods and services.
This index series was introduced for mid-January 2012. The weighting pattern used in the index was based on the results of the 2009-2010 Household Budget Survey. The review of item headings resulted in 632 item headings in the CPI basket of goods and services. This basket was updated in January 2015 to 634 items with the addition of sewage collection and water supply.
This index series was introduced for mid-January 2017. The weighting pattern used in the index was based on the results of the 2015/16 Household Budget Survey. The review of item headings resulted in 615 item headings in the CPI basket of goods and services.