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13 Seasonally adjusted chain volume figures are calculated from seasonally adjusted figures expressed in the prices of the previous year. As with original data, the seasonally adjusted chain volume measures are benchmarked to annual original estimates. As a consequence, the seasonally adjusted chain volume measures sum to the corresponding annual original figures-unlike their current price counterparts.
14 Given the qualifications regarding the accuracy and reliability of the quarterly national accounts, the ABS considers that trend estimates provide the best guide to the underlying movements, and are more suitable than either the seasonally adjusted or original data for most business decisions and policy advice.
15 A trend estimate is obtained by removing the irregular component from the seasonally adjusted series. For estimates in this publication, it is calculated using a centred 7-term Henderson moving average of the seasonally adjusted series. Estimates for the three most recent quarters cannot be calculated using this centred average method; instead an asymmetric average is used. This can lead to revisions in the trend estimates for the last three quarters when data become available for later quarters, even if none of the original data for earlier quarters has changed. Trend estimates for aggregates such as GDP are derived directly, rather than as the sum of components. As a result, the sum of the trend estimates of individual components of a particular aggregate will not sum to the overall trend estimate of the aggregate for the latest three quarters. As advised in the June quarter 1998 issue of this publication, this approach provides higher quality trend estimates for key aggregates, particularly GDP.
16 The higher the 'irregular' component in a series, then the greater the likelihood that trend estimates for the latest quarters will be revised as more observations become available. However, it is important to note that this does not make the trend series inferior to the seasonally adjusted or original series. In fact, in such cases the effect of the irregular component on overall movements is likely to be even more in the seasonally adjusted and the original estimates than in the trend series.
17 For more information about ABS procedures for deriving trend estimates and an analysis of the advantage of using them over alternative techniques for monitoring trends, see Information Paper: A Guide to Interpreting Time Series - Monitoring 'Trends': an Overview (Cat. no. 1348.0) or contact the Assistant Director, Time Series Analysis on Canberra 02 6252 6345.
18 Two feature articles which have appeared in the ABS monthly publication Australian Economic Indicators (Cat. no. 1350.0) may also be of interest: Picking Turning Points in the Economy (April 1991), and Smarter Data Use (March 1992).
State and Territory versus Australian series
19 For trend and seasonally adjusted series, the sum of the States and Territories generally does not equal the corresponding estimate for 'total Australia', nor are the quarter-to-quarter movements identical. On a few occasions, these differences have been significant, particularly for the seasonally adjusted series. This reflects both the shorter span of data available for seasonal analysis at the State level and the fact that seasonal analysis is generally carried out at a more aggregated level than for the 'total Australia' series. The State and Territory trend and seasonally adjusted series are less accurate than the Australian data. However, as the State and Territory time series lengthen, the quarterly movements in the sum of the State estimates should more closely match those in the Australian series.
GROSS DOMESTIC PRODUCT (GDP)
20 GDP can be derived by three broad approaches: the income approach (I), the expenditure approach (E) and the production approach (P). A description of each approach is provided in the following paragraphs. While each measure should, conceptually, deliver the same estimate of GDP, if the three measures are compiled independently using different data sources then different estimates of GDP result. However, the Australian national accounts estimates have been integrated with annual balanced supply and use tables. These tables have been compiled from 1994-95, up to the year preceding the latest completed financial year. As integration with balanced supply and use tables ensures that the same estimate of GDP is obtained from the three approaches, annual estimates using the I, E and P approaches are identical for the years for which these tables are available.
21 Prior to 1994-95, and for quarterly estimates for all years, the estimates using each approach are based on independent sources, and there are usually differences between the I, E and P estimates. Nevertheless, for these periods, a single estimate of GDP has been compiled. In chain volume terms, GDP is derived by averaging the chain volume estimates obtained from each of the three independent approaches. The current price estimate of GDP is obtained by reflating the average chain volume estimate by the implicit price deflator derived from the expenditure-based estimates.
22 As a result of the above methods:
INCOME APPROACH (I)
23 GDP using the income approach is derived as the sum of factor incomes, consumption of fixed capital (depreciation) and taxes less subsidies on production and imports. Volume estimates are derived by deflating current price estimates by the implicit price deflator from the expenditure approach.
EXPENDITURE APPROACH (E)
24 GDP using the expenditure approach is derived as the sum of all final expenditures, changes in inventories and exports of goods and services less imports of goods and services. Volume estimates are derived for each of the components as well as for their sum.
PRODUCTION APPROACH (P)
25 GDP using the production approach is derived as the sum of gross value added for each industry, at basic prices, plus taxes less subsidies on products. Basic values represent the amounts received by producers, including the value of any subsidies on products, but before any taxes on products. The difference between the sum over all industries of gross value added at basic prices, and GDP at market (or purchasers) prices, is the value of taxes less subsidies on products.
26 In this publication, only volume estimates compiled using the production approach have been shown. These estimates are derived by extrapolating annual volume measures using various indicators. The information necessary to compile comprehensive current price estimates using the production approach is not available quarterly.
IMPLICIT PRICE DEFLATORS (IPD)
27 The quarterly implicit price deflators (IPDs) are derived by dividing seasonally adjusted current price estimates by the corresponding chain volume estimates. Movements in IPDs can be greatly affected by changes in the physical composition of the aggregates and their components. For this reason, quarterly IPDs derived from seasonally adjusted or trend data are preferred to those using original data. For further information see Chapter 10 of 5216.0.
CHAIN PRICE INDEXES
28 The chain price indexes appearing in this publication are annually-reweighted chain Laspeyres price indexes referenced to the same year as the chain volume estimates. They can be thought of as a series of indexes measuring price change from a base year to quarters in the following year using current price values in the base year as weights, linked together to form a continuous time series. In other words, chain price indexes are constructed in a similar fashion to the chain volume indexes. Quarterly chain price indexes are benchmarked to annual chain indexes in the same way as their chain volume counterparts. Unlike implicit price deflators, chain price indexes measure only the impact of price change.
ANALYSIS OF CONTRIBUTIONS TO GROWTH
29 Table 6 analyses the contribution provided by each major component to the percentage change in the seasonally adjusted chain volume estimates of GDP. The contributions to growth of the components of GDP do not always add exactly to the growth in GDP. This can happen as a result of rounding and the lack of additivity of the chain volume estimates prior to the latest complete financial year. The formula used to calculate the contribution of each aggregate to the growth in GDP is:
A(t) - value of aggregate A in quarter under consideration
A(t-1) - value of aggregate A in previous quarter
GDP(t-1) - value of GDP in previous quarter
TERMS OF TRADE
30 There are several ways of measuring the terms of trade. In this publication, the following index is used:
31 Estimates of the terms of trade are shown in tables 1, 9, 42 and 45.
REAL GROSS DOMESTIC INCOME
32 Chain volume GDP is a measure of the volume of goods and services produced in Australia. If the terms of trade change significantly over the period of comparison, then this measure of GDP will not accurately reflect the change in real purchasing power of the income generated by domestic production. (See the Technical Note included in the September 1993 issue of this publication for a more detailed discussion.) A better measure of the real purchasing power of income generated by domestic production is chain volume GDP adjusted for the terms of trade effect, which is referred to as real gross domestic income (or real GDI). To obtain an estimate of real GDI, the following adjustment is made to the volume measures of GDP, prior to chaining:
GROSS DOMESTIC PRODUCT PER HOUR WORKED
33 Movements in chain volume estimates of GDP per hour worked shown in tables 1 and 42 are commonly interpreted as changes in labour productivity. However, it should be noted that these measures reflect not only the contribution of labour to changes in production per hour worked, but also the contribution of capital and other factors (such as managerial efficiency, economies of scale, etc.).
34 When analysing labour productivity indexes it is critical to note that they are subject to the vagaries of the growth (or business) cycle as well as the effects of any measurement error in either output or labour input. Differences in the amplitude and phase of the input and output cycles can result in labour productivity indexes deviating substantially from their longer-term trend. Analytical work undertaken within the ABS suggests that movements in employment and hours worked tend to lag movements in GDP. Over a twenty year period, the lag at turning points in the growth cycle varied between zero and four quarters, with the average being between two and three quarters. The implication is that, in the period of the growth cycle when the growth in output is declining, indexes of labour productivity are likely to decline, particularly if rapid growth in GDP is abruptly ended. Conversely, labour productivity indexes are likely to grow strongly when the economy comes out of a cyclical trough.
35 A simple way to estimate the underlying trend in labour productivity is to compare the values of a labour productivity index spanning a growth cycle e.g. from the peak of one growth cycle to the peak of another. This analysis assumes that labour is being utilized to the same degree at each growth cycle peak. Average annual growth rates, over growth cycles, of estimates of gross product per hour worked in the market sector are shown in Australian System of National Accounts (Cat. no. 5204.0).
36 Five industries are excluded from the market sector: Property and business services; Government administration and defence; Education; Health and community services; and Personal and other services. These are excluded because their outputs are not marketed and/or because their outputs are derived either wholly or primarily by using either deflated input cost data or hours worked as indicators of output. The chain volume measure of the production of a group of industries referred to as the market sector is defined to be the chain volume estimate of industry gross value added of all industries less the above five industries, less Ownership of dwellings (for which an index of capital services is used as the indicator of output), plus taxes less subsidies on products attributable to the market sector industries.
INDEXES OF HOURS WORKED
37 The quarterly hours worked indexes used to derive the indexes of GDP per hour worked and market sector GDP per hour worked comprise all labour engaged in the production of goods and services and include not only hours worked by civilian wage and salary earners but also those of employers, self-employed persons, persons working one hour or more without pay in a family business or on a farm, and members of the Australian defence forces.
PRIVATE BUSINESS INVESTMENT
38 Private business investment is presented in table 41. It is defined as:
PRIVATE NON-FARM INVENTORIES TO TOTAL SALES RATIO
39 This ratio is presented in table 41. The denominator of this ratio, which is calculated using current price estimates, is defined as:
IMPORTS TO DOMESTIC SALES RATIO
40 This ratio is presented in table 41. The numerator of this ratio, which is calculated using current price estimates, is imports of goods. The denominator-domestic sales-is defined as:
HOUSEHOLD SAVING RATIO
41 This is the ratio of household net saving to household net disposable income. Household net saving is calculated as household net disposable income less household final consumption expenditure. Household net disposable income is calculated as household gross disposable income less household consumption of fixed capital. The ratio is shown as a memorandum item in tables 31 and 32.
GDP PER CAPITA
42 This is the ratio of the chain volume estimate of GDP to an estimate of the resident Australian population. Population estimates are as published in the quarterly publication Australian Demographic Statistics (Cat. no. 3101.0) or, where not yet available, projections based on current trends.
AVERAGE COMPENSATION PER EMPLOYEE
43 The average compensation per employee can be measured in a number of ways. The series shown as a memorandum item in a number of tables in this publication is calculated as total compensation of employees divided by the number of wage and salary earners from the monthly Labour Force Survey.
44 In addition to the publications already mentioned, others of interest include:
Australian System of National Accounts (Cat. no. 5204.0)-annual
Australian National Accounts: State Accounts (Cat. no. 5220.0)-annual
Australian National Accounts: Financial Accounts (Cat. no. 5232.0)-quarterly
45 Current publications produced by the ABS are listed in the Catalogue of Publications and Products (cat. no. 1101.0). The ABS also issues, on Tuesdays and Fridays, a Release Advice (cat. no. 1105.0) which lists publications to be released in the next few days. The Catalogue and Release Advice are available from any ABS office.
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