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MAIN CONCEPTUAL DIFFERENCES FROM THE CPI
3 A living cost index is intended to be used to assess changes over time in the purchasing power of the after-tax incomes of households. It is therefore concerned with measuring the impact of changes in prices on the out-of-pocket expenses incurred by households to gain access to consumer goods and services. The item coverage of such an index is determined by reference to the actual money outlays of households on all but investment items.
4 There are a number of ways to construct a consumer price index with at least three widely accepted alternative approaches used by national statistical agencies:
5 From September quarter 1998, the CPI has been designed specifically to measure price inflation for the household sector as a whole. It is therefore constructed using the acquisitions method.
6 The indexes represent the conceptually preferred measures for assessing the impact of changes in prices on the disposable incomes of households. In other words, these indexes are particularly suited for assessing whether the disposable incomes of households have kept pace with price changes. The Australian Consumer Price Index (CPI), on the other hand, is designed to measure price inflation for the household sector as a whole and, as such, is not the conceptually ideal measure for assessing the impact of price changes on the disposable incomes of households. The ALCIs are constructed using the outlays approach.
7 In practice, for most goods and services purchased by the reference population, outlays and acquisition occur within a relatively short space of time. There are three areas of expenditure in which these conceptual approaches provide significantly different results:
8 Under the acquisitions approach in the CPI, the net purchase of housing, the increase in volume of housing due to renovations and extensions and other costs (e.g. maintenance costs and council rates) are included for owner-occupied housing. Changes in rental are measured for that part of the reference population that resides in rented dwellings.
9 Under the outlays approach in these living cost indexes, the changes in the amount of interest paid on mortgages and other costs (e.g. maintenance costs and council rates) are included for owner-occupied housing. Changes in rental are measured for that part of the reference population that resides in rented dwellings.
10 Insurance (other than health insurance) is also treated differently in the living cost indexes. Under the acquisitions approach, the weight for insurance in the CPI relates to the net value of the service provided by the insurance company. In simple terms, this represents the amount of premiums paid by households less the amounts reimbursed by way of claims. Under the outlays approach in these living cost indexes, the weight relates to the gross value of insurance premiums paid by households.
11 Financial services are also treated differently in the living cost indexes. The living cost indexes include mortgage interest and consumer credit charges but exclude all other financial services.
12 Regional weights for the CPI are based on the HES distributions in the capital cities, however the weights in the analytical living cost indexes are based on the HES distributions for the State or Territory. This produces more reliable weights for some of the smaller expenditure categories in these living cost indexes.
13 Construction of the living cost indexes was essentially undertaken in three stages. Stage one was concerned with calculating weights representative of the expenditure patterns of the defined household types. Stage two involved identifying appropriate measures of price change for each of the expenditure weights. The third and final stage was to use the weights to aggregate or average the price change measures.
14 Item weights for the population subgroups were derived mainly from the HES. However, unlike the CPI where estimates are calculated separately for each of the eight capital cities, population subgroup estimates were calculated at the national level only. This was necessary because the subgroup sample sizes at the capital city level were simply too small, for at least some groups, to produce reliable estimates at the capital city level. For this reason it is not possible to produce living cost indexes at the individual city level.
15 The measures of price change, with the exception of those for interest charges, were sourced from the CPI. Price measures for interest charges have been maintained separately by the ABS on a basis comparable with those employed in the CPI prior to September quarter 1998.
16 While most item price indexes were constructed by direct reference to the equivalent CPI expenditure class indexes, some were constructed by reference to lower level CPI price data. The exceptions relate to those items where it is known that different household types face different prices, such as subsidised public transport fares for senior citizens.
17 These indexes were constructed using three sets of weights. The first set of weights, based on the 1993-94 HES, was used to construct the indexes from June quarter 1998 to June quarter 2000. The second set of weights, based on the 1998-99 HES, was used to construct the indexes from June quarter 2000 to June quarter 2005. The third set of weights, based on the 2003-04 (HES), was used to construct the indexes from September quarter 2005 onwards. All indexes are linked at June quarter 2005.
EXPENDITURE PATTERNS OF THE SELECTED HOUSEHOLD TYPES
18 Calculation of the aggregate impact of price changes on each of the household types involves weighting together the price movements recorded for individual goods and services. For each household type, the weight assigned to any particular good or service reflects the proportion of total household expenditure accounted for by expenditure on the item.
19 Table 1 shows average weekly expenditure per household during 2003-04 for each of the four household types, at June quarter 2005 prices. The commodity groups used correspond to the commodity groups used for the current (15th series) CPI.
20 Table 1 illustrates significant differences in expenditures, both in total and at the individual commodity group level across the household types. Although differences in incomes are likely to be a major reason for this, other factors such as the demographic make-up of the households and dwelling tenure would also play a part. For example, age pensioner households have on average the lowest number of persons per household and self-funded retiree households have a higher than average rate of outright home ownership.
21 Table 2 presents the same data in percentage terms, along with the CPI for comparison purposes. It is this data that produces the expenditure shares or weights that are given to each household type, and to which the price movements are applied.
22 There are some notable differences in the expenditure weights across the household types. For example, the proportion of expenditure allocated to Food is highest for age pensioner households. It is also relatively high for other government transfer recipient households. Employee households allocate a higher proportion of their expenditures to Transportation, Education and Financial and insurance services (which includes interest charges) than the other household types. Other government transfer recipients allocate higher proportions of their expenditures to Housing, Alcohol and tobacco and Communication. Self-funded retiree households have higher relative expenditures on Household contents and services and Recreation than the other household types. Health costs account for a significantly higher proportion of expenditure of age pensioner and self-funded retiree households.
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