Producer Price Indexes, Australia methodology

From the September quarter 2012 Producer Price Indexes relate to all products that are used or produced by establishments classified, according to ANZSIC 2006, to a specific industry, including secondary production. Prior to the September quarter 2012, Producer Price Indexes related to products primary to a specific industry. Primary products are defined as products which are strictly classified to a particular industry, as defined by the Australian and New Zealand Standard Industrial Classification, 2006 edition (ANZSIC 2006). The production of products outside these strict industry classifications are considered as secondary production.

Producer Price Indexes are compiled on a gross industry basis. This means that the scope of the indexes includes all transactions occurring within an industry and between that industry and other industries. This approach aligns with the principal purpose of the Producer Price Indexes, which is to support the compilation of the Australian National Accounts and Balance of Payments.

Producer Price Indexes are constructed as either output or input measures. The output Producer Price Indexes relate to products produced by establishments classified to a specific industry. The input Producer Price Indexes relate to products used by establishments classified to specific industries.

The valuation basis for the transactions covered by an output index is basic prices, defined as the amount received by the producer exclusive of any taxes on products and transport and trade margins (i.e. the pricing point is ex-factory, ex-farm, ex-service provider, etc.).

The valuation basis for the transactions covered by an input index is purchasers' prices, defined as the amount paid by the purchaser inclusive of any non-deductible taxes on products and transport and trade margins (i.e. the prices recorded in the index should be those relating to products 'delivered into store', 'delivered on site', etc.).

In reality, industry practice may mean that it is sometimes necessary to diverge from the conceptually ideal price in order to obtain actual transaction prices. For example, although the conceptually ideal price for the Output of the Manufacturing industries price indexes is ex-factory, in cases where costs such as handling and distribution are built into the manufacturer's selling price, they will be included in the index.

Similarly, for input indexes such as the Input to the House construction industry price index, which has a conceptually ideal price of delivered on site, it has sometimes been necessary to use the nearest actual transaction price available, e.g. prices of products supplied and fixed.

The Goods and Services Tax (GST) is excluded from all the prices recorded in the Producer Price Indexes. The GST is a deductible business-to-business transaction. In the case of Services industries output indexes relating to business-to-household transactions, the GST is also excluded as the price indexes are valued in basic prices (i.e. exclusive of product taxes).

The indexes are weighted based on the Lowe indexes i.e. proportional weights for each of the components are fixed in some specified earlier period. The list of products and the weights are updated periodically to ensure they remain representative of the activities of providers in the Australian economy. Index series compiled using updated weights are linked to earlier series to maintain a continuous series. Upper level weights are derived from the Australian National Accounts: Input-Output Tables - Electronic Publication, 2012-13 (cat. no. 5209.0.55.001) as well as other ABS and industry sources.

The main sources of ongoing price data are samples of business establishments. These can be buyers or sellers, dependent on whether the price is contributing to an input or an output price index. Practical considerations such as the relative degree of concentration of buyers and of sellers, along with the implications for sample size and cost will be taken into account when determining samples.

The main pricing methodology is specification pricing, under which a manageable sample of precisely specified products is selected, in consultation with each reporting establishment, for repeat pricing. In specifying the products, care is taken to ensure that they are fully defined in terms of all the characteristics which influence their transaction prices. As such, all the relevant technical characteristics need to be described (e.g. make, model and features) along with the unit of sale, type of packaging, conditions of sale (e.g. delivered, payment within 30 days) etc.

When the quality or the specifications of a product being priced change over time, adjustments are made to the reported prices so that the index captures only pure price change. That is, any element of price change attributable to a change in quality is accounted for and removed wherever possible. If there is an increase (decrease) in the quality of a product, the price is adjusted upwards (downwards) to reflect the value of the quality change to the provider of the product. This technique is known as pricing to constant quality.

Another important consideration in establishing and maintaining price collections is to ensure that the prices reported are actual market transaction prices. That is, they must reflect the actual prices received (or paid) after taking into account all discounts applied to the transactions whether they be volume discounts, settlement discounts or competitive price cutting discounts which are likely to fluctuate with market conditions.

Any rebates also need to be considered. The collection of nominal list prices, or book prices, is unlikely to yield reliable price indexes and could result in quite misleading results if fluctuations in transaction prices are not captured. The ABS therefore asks provider business establishments to report details of the discounts they offer so that actual transaction prices can be calculated.

Specification pricing is not feasible in cases where the products are unique and not reproduced over time, e.g. the output of the Construction industries indexes and many customised business services. As a result, alternative pricing techniques need to be used, which sometimes require a compromise. Some of the approaches adopted include the use of model pricing, collecting unit values for reasonably homogeneous components of a product, input pricing and collecting charge-out rates (e.g. for a legal service).

Where prices of products are expected to move in a similar way, many of the directly priced products are taken to be representative of similarly classified products which are not directly priced. The main advantages of this are more effective use of ABS resources and a reduced burden on business establishments who provide the ABS with price information.

From the September quarter 2012, all Producer Price Indexes have been constructed in accordance with the Australian and New Zealand Standard Industrial Classification (ANZSIC), 2006 edition (cat. no. 1292.0). Prior to the September quarter 2012, the SOP series (Tables 1-10) were on an ANZSIC 1993 basis, while the other Producer Price Indexes relating to products primary to specific industries were based on ANZSIC 2006 from the September quarter 2009 onwards. Further information on the latest industrial classification can be found in the Information Paper: Update on ANZSIC 2006 Implementation for Producer and International Trade Price Indexes, Australia (cat. no. 6427.0.55.002).

Table 1 present Final demand index for the supply of products to the Australian economy. The index covers both domestically produced and imported products, individually and aggregated. The Final demand is compiled from data used in the industry classification indexes, the international trade indexes and some additional data collections. The indexes are calculated on the index reference period 2011-12 = 100.0.

Final products are those that are ready to be sold for immediate consumption, capital formation or export.

In concept the valuation of transactions in the Final demand index is basic prices (see Valuation basis section). However, the use of component series from existing ABS price collections in some cases results in the valuation diverging from this ideal.

The Output of the Mining industries Producer Price Indexes relates to products that are produced by establishments classified to ANZSIC 2006 Mining industries. The Input to the Coal mining industry index relates to products used by establishments classified to ANZSIC 2006 Subdivision 06 - Coal mining.

The Output of the Mining industries indexes is available on the ABS website. Table 36 presents price indexes of the outputs from establishments classified to the selected Mining industries. Table 11 presents the Input to the Coal mining industry price index. The valuation basis is basic prices for the output indexes and purchasers' prices for the input indexes (see Valuation basis section). Therefore, as far as possible, extraction prices are included in the output indexes and prices for products delivered to the mine site or the primary storage area for a group of mines are reflected in the input index.

The Output of the Mining industries price indexes (Table 36) measure changes in prices of the outputs from selected Mining industries. Presented in this table are: Gas extraction, Domestic; Gas extraction, Domestic, East coast market; and Gas extraction, Domestic, Western Australia. These indexes are a component of the ANZSIC Subdivision 07 - Oil and Gas Extraction. The Input of the Coal mining industry (Table 11) products are reflective of all inputs into ANZSIC Subdivision 06 - Coal mining. The weights and products in Mining industry Producer Price Indexes have been derived from the Australian National Accounts: Input-Output Tables - Electronic Publication, 2012-13 (cat. no. 5209.0.55.001), in combination with data from other industry sources.

The Output of the Manufacturing industries Producer Price Indexes relate to all products that are produced by establishments classified to a specific industry, whereas the Input to the Manufacturing industries price indexes relate to all products used by establishments classified to a specific industry. They are important sources of data for the Final demand and previously the SOP indexes.

The Manufacturing industries indexes are available on the ABS website http://www.abs.gov.au. Table 12 presents individual price indexes of Output of the Manufacturing industries as well as quarter-on-quarter and year-on-year percentage changes. Table 13 presents the Input to the Manufacturing industries price indexes as well as quarter-on-quarter and year-on-year percentage changes. Basic prices are used for output indexes and purchasers' prices for input indexes (see Valuation basis section). Therefore, as far as possible, ex-factory prices are included in the output indexes. Delivered into factory prices are included in the input indexes.

Prior to the September quarter 2009, the Manufacturing industries indexes were constructed on a net sector basis with intra-sector transactions netted out. From the September quarter 2009, the Manufacturing industries indexes are constructed on a gross industry basis. The net and gross industry methods are more easily explained by way of an example. The transactions captured for a motor vehicle manufacturing GROSS industry index would include both the sales of the parts (including sales of parts to other business establishments in the same industry) and the sales of the finished cars - even though the price change of the parts would be included in the price change of the cars. On the other hand, a motor vehicle manufacturing NET industry index would measure only the price change of motor vehicles sold to other industries of the economy and would exclude the price change of the parts (sold to business establishments in the same industry) as a separate product.

From the September quarter 2009 onwards the Output of the Manufacturing industries indexes (Table 12) measure changes in the prices of products that are classified to ANZSIC 2006. Manufacturing industries that are sold or transferred to domestic establishments within or outside the Manufacturing industries for further processing, intermediate use or used as capital equipment or exported.

Similarly, the Output of the Manufacturing industries indexes for products classified to ANZSIC 2006 subdivisions and groups (Table 12) measure transactions within and outside the subdivision or group. Prior to the September quarter 2009 these series were constructed on a net sector basis. They excluded intermediate transactions in products classified to the ANZSIC 2006 subdivision that were sold or transferred within that subdivision or group for further processing.

From the September quarter 2009 onwards the Input to the Manufacturing industries indexes (Table 13) measure changes in the prices of products used in ANZSIC 2006 Manufacturing industries that have been purchased or transferred in from domestic establishments within or outside the Manufacturing industries, or imported. Similarly, the Input to the Manufacturing industries indexes for subdivisions (Table 14) measure input purchases or transfers within and outside the subdivision.

The index structures and weighting patterns for the Manufacturing industries input and output ANZSIC 2006 division indexes are presented in the Information Paper: Producer Price Indexes Weighting Patterns (cat. no. 6427.0.55.006). Index structures and weighting patterns for the associated ANZSIC 2006 subdivisions and groups are available from the ABS website https://www.abs.gov.au as data cubes in that information paper.

The Output of the Construction industries Producer Price Indexes relate to outputs classified to ANZSIC 2006 Construction industries. The Input to the House construction industry index relates to products used by establishments classified to ANZSIC 2006 Class 3011 - House construction. The Output of the Construction indexes are important sources of data for Final demand.

The Output of the Construction industries indexes is available on the ABS website. Table 17 presents price indexes of the outputs from establishments classified to the Building construction subdivision and selected Construction industries classes. Table 18 presents the Input to the House construction industry price indexes as well as quarter-on-quarter and year-on-year percentage changes for each of the indexes. The valuation basis is basic prices for the output indexes and purchasers' prices for the input indexes (see Valuation basis section). Therefore, as far as possible, builders' selling prices are reflected in the output indexes and delivered on site prices are reflected in the input indexes.

The Output of the Construction industries price indexes (Table 17) measure changes in prices of the outputs from selected Construction industries. Presented in this table are the ANZSIC 2006 Subdivision 30 - Building construction industries, which consists of three classes: Class 3011 - House construction, Class 3019 - Other residential building construction and Class 3020 - Non-residential building construction. Outputs from ANZSIC 2006 Subdivision 31, which consists of the Class 3101 - Road and bridge construction and Class 3109 - Other heavy and civil engineering construction, are also presented in this table.

The Input to the House construction industry price indexes (Table 18) measure changes in prices of products used in house construction, where a house is defined as a detached building predominantly used for long-term residential purposes and consisting of only one dwelling unit. The scope of the index approximates the ANZSIC 2006 Class 3011 - House construction.

The Input to the House construction index does not explicitly cover alterations, additions, renovations and repairs. It relates to the greater capital city statistical area for each state capital city.

ANZSIC 2006 class output indexes at the national level are aggregated to the relevant group and subdivision using weights derived primarily from values of the supply of new general construction products in Australia using the Australian National Accounts: Input-Output Tables - Electronic Publication, 2012-13 (cat. no. 5209.0.55.001). ANZSIC 2006 class indexes at the State and Territory level are aggregated to the national level using proportions based on the value of work done by State and Territory and by type of construction as measured by the Building Activity, Australia (cat. no. 8752.0) for the 2010 and 2011 calendar years. The indexes generally use prices for work undertaken in each capital city, as construction activity in the city is taken to represent the whole State or Territory. For Queensland, however, other residential building construction and non-residential building construction also use prices obtained for North Queensland. The ANZSIC 2006 Class 3109 index is obtained as aggregate of engineering construction category indexes compiled using prices sourced from ABS's existing indexes. The proportions used in the aggregate are based on the value of work done by State and Territory and by construction category, as measured by the Engineering Construction Activity, Australia (cat. no. 8762.0).

The products and weights for the price index of Input to the House construction industry were derived from reported quantities of each product used in selected representative houses in the three years ending 2002-03. The weighting pattern for each capital city index will reflect variations in prices for the cities as applied to an Australian average basket of house building materials, with some allowance for city specific building practices e.g. the differential use of steel and timber materials in Perth and Adelaide compared with the other capital cities. The weighting patterns for the price index of Input into the House construction industry are set out in Appendix 2 of the September quarter 2005 issue of this publication. Note that the weights shown are values based on the quantities of various materials used in house building over the three years ended 2002-03, valued at the September quarter 2005 prices.

The Output of the Retail Trade Price Index (RTPI) is a measure of the price of the retail distribution service and is compiled from retail margins data for product groups classified to ANZSIC 2006 Division G Retail Trade. The Output of the Retail Trade Price Index (RTPI) index is available on the ABS website http://www.abs.gov.au. First results were published in November 2013, by way of experimental indexes, in the September Quarter 2013 issue of this publication (cat. no. 6427.0).

The Output of the Retail Trade Industry cannot be compiled with the same timeliness as other Producer Price Indexes. The basic data required for the construction of the Producer Price Indexes for the Output of the Retail Trade Industry are quarterly sales and cost of goods sold (COGS). These economic flow data cannot be collected until sometime after the end of the reference quarter. By comparison, price indexes for goods and some services are based on point in time prices prevailing at selected dates during the quarter. Further, calculation of the RTPI requires the latest period CPI data to be available for price updating purposes. From the September quarter 2017, the measurement of retail margin prices is done at the enterprise level. Prior to this it was measured at the outlet level. The entire series has been revised to ensure it's on a consistent basis.

Retail trade margins data are collected by the ABS for selected unpublished Supply and Use Product Classifications (SUPC) with the highest contribution to total retail trade margins and where data collection is feasible. A sample of businesses are selected from those classified to ANZSIC 2006 Division G Retail Trade. The Retail Trade Margins Survey (RTMS) collects retail trade data on sales and cost of goods sold (COGS) from primarily large retail businesses. A partial coverage collection approach is used where large businesses represent the retail trade margins of all sizes of retail business. Medium sized businesses are included only where industry concentration is not sufficient to exclude them and/or when the retail trade margins of large businesses are not sufficiently representative of those of medium sized businesses. The RTMS excludes small businesses, except where they are a part of a franchise operation. Price indexes and movements are provided in Table 31.

The RTPI is compiled from retail margins data for selected unpublished product groups, classified to ANZSIC 2006 Division G Retail Trade with weights updated and indexes chained annually each June quarter.

The weights used in the aggregation stages of the national RTPI are unpublished national SUPC retail trade margin shares, obtained from the National Accounts Supply and Use (S-U) tables annually.

The Output of Services industries indexes are available on the ABS website. Tables 20-27, 34-35 present index numbers for selected services industries classified to the following ANZSIC 2006 divisions: Accommodation and food services industries, Transport, postal and warehousing industries, Information media and telecommunications industries, Rental, hiring and real estate services industries, Professional, scientific and technical services industries, Administrative and support services industries, Public administration and safety industries, Education and training industries, Health care and social assistance industries and Other services industries. The valuation basis for each index is basic prices (see Valuation basis section). Prices used in the indexes relate to the prices received by the producer of the service.

The currently available services industries indexes represent the results to date of a program to progressively extend the scope of the Producer Price Indexes into the services industries of the Australian economy. First results from the program were published in March 1999, by way of experimental indexes, in the Information Paper: Producer Price Index Developments, 1999 (cat. no. 6422.0). Similarly, changes to the indexes published from the September quarter 2009 on the ANZSIC 2006 basis have been documented in the Information Paper: Update on ANZSIC 2006 Implementation for Producer and International Trade Price Indexes, Australia, 2009 (cat. no. 6427.0.55.002). Expanded coverage and improved indexes will be progressively implemented through the Services Producer Price Indexes Development program.

The Output of the Services industries price indexes measure changes in prices of services classified to selected ANZSIC 2006 industries. Output price indexes for these industries are provided in Tables 20-27, 34-35.

From the September quarter 2012, ANZSIC 2006 class indexes are aggregated to the relevant group, subdivision and division using weights derived from the Australian National Accounts: Input-Output Tables - Electronic Publication, 2012-13 (cat. no. 5209.0.55.001), in combination with data from other ABS surveys and industry sources.

The development of the services industries price collections has involved a wide range of diverse industries with different measurement challenges. Accordingly, extensive consultation with industry associations and individual business establishments has been undertaken to determine the most viable approach, on a case-by-case basis.

Characteristics found within the services industries of the Australian economy have complicated the task of price measurement.

The tendency within many industries to provide unique, one-off services tailored to the needs of individual customers has posed difficulties in establishing continuity of pricing to constant quality.

The 'bundling' of a range of different component services within one transaction or contract has required investigation of the feasibility of 'unbundling', that is, obtaining separate prices for each component of the total service. Where this has not proven to be feasible, the whole service bundle has been priced.

Provider business establishments are asked to report details of any discounts they offer so that actual transaction prices can be calculated. However, as discounts are sometimes negotiated between individual buyers and sellers in relation to particular transactions, identifying discounts has not always been straightforward.

The deregulation of some services industries leads to structural changes and more complex pricing practices. To deal with this, samples are continually updated to incorporate new businesses and pricing methodologies are reviewed over time.

The shifting trend in the use of administrative and transaction data across the Prices Branch has resulted in the utilisation of Average Unit Values (AUVs). The Producer Price Indexes incorporate AUVs as a measure of price change for services industries that are homogeneous and of constant quality.

It is planned to make available indexes for the majority of the remaining ANZSIC 2006 classes within the Services industries after they have been developed from experimental to production status. At such time these new indexes would contribute to the broader Final demand index in this publication and associated outputs available on the ABS website.

Index numbers for financial years are simple averages of the relevant quarterly index numbers.

Indexes for the Input to the House construction industry are presented separately for each of the six state capital cities and indexes for the Output of Construction industry are presented separately for each of the states and territories (i.e. capital city or state/territory). These indexes measure price change over time; they do not measure differences in price levels between capital cities or states/territories.

Published index numbers are rounded to one decimal place. Percentage change movements are calculated from the index numbers and then rounded to one decimal place. Rounding errors can occur, causing discrepancies (e.g. when calculating percentage changes of aggregates and their components).

Care should be exercised when interpreting quarter-to-quarter movements in the indexes as short-term movements do not necessarily indicate changes in trend.

Movements in indexes from one period to another can be expressed either as changes in index points or as percentage changes. The following example illustrates the method of calculating index points changes and percentage changes between any two periods:

Final demand index numbers
June quarter 2019 111.6 (see Table 1)
less June quarter 2018 109.4 (see Table 1)
Change in index points 2.2
Percentage change 2.2/109.4 X 100 = 2.0% (see Table 2)

Data cubes for the Final demand provides analyses of the index points contribution of each ANZSIC group towards the Final demand indexes, for both total and separately for domestic and imported commodities. For example, in the domestic component of Final demand, Petroleum refining and petroleum fuel manufacturing contributed 0.60 index points to the Final domestic demand index number of 110.9 for the June quarter 2019 and 0.06 index points to the net change of 0.3 index points between the March 2019 and June 2019 quarters.

Further information on price index developments in the ABS is presented in the following publications:

Information Paper: Producer and International Trade Price Indexes; Concepts, Sources and Methods (cat. no. 6429.0)

Information Paper: Changes to Time Series Spreadsheets for Producer Price Indexes, Australia (cat. no. 6427.0.55.001)

Information Paper: Update on ANZSIC 2006 Implementation for Producer and International Trade Price Indexes, Australia (cat. no. 6427.0.55.002)

Information Paper: Review of the Producer and International Trade Price Indexes (cat. no. 6427.0.55.003)

Information Paper: Outcome of the Review of the Producer and International Trade Price Indexes (cat. no. 6427.0.55.004)

Information Paper: Implementation of the Review of the Producer and International Trade Price Indexes (cat. no. 6427.0.55.005)

Information Paper: Producer Price Indexes Weighting Patterns (cat. no. 6427.0.55.006)

Information Paper: An Analytical Framework for Price Indexes in Australia (cat. no. 6421.0)

Information Paper: Producer Price Index Developments (cat. no. 6422.0)

Information Paper: Review of the Import Price Index and Export Price Index, Australia (cat. no. 6424.0)

Information Paper: Price Indexes and The New Tax System (cat. no. 6425.0)

Australian and New Zealand Standard Industrial Classification (ANZSIC),(Revision 2.0) (cat. no. 1292.0)

Information Paper: Update on ANZSIC 2006 Implementation (cat. no. 1295.0.55.001)
 

Users may also wish to refer to the following related publications and other data products that are available free of charge from the ABS website.

International Trade Price Indexes, Australia (cat. no. 6457.0)

Consumer Price Index, Australia (cat. no. 6401.0)

Wage Price Index, Australia (cat. no. 6345.0)

Residential Property Price Indexes: Eight Capital Cities (cat.no. 6416.0)

Australian National Accounts: Input-Output Tables (cat. no. 5209.0.55.001)

Balance of Payments and International Investment Position, Australia (cat. no. 5302.0)

Current publications and other products released by the ABS are listed on the ABS website. The ABS also issues a daily Release Advice on the website which details products to be released in the week ahead.

The ABS is independent of government, with the Australian Bureau of Statistics Act 1975 giving the Statistician the power to control the operations of the ABS. For further information on the institutional environment of the Australian Bureau of Statistics (ABS), including the legislative obligations of the ABS, financing and governance arrangements, and mechanisms for scrutiny of ABS operations, please see ABS Institutional Environment.

The Australian Producer Price Indexes (PPI) measure the changes in the prices of goods and services as they either leave the place of production or as they enter the production process. Thus, producer price indexes can be constructed as either output measures or input measures. An input PPI measures the rate of change in the prices of goods and services purchased as inputs by the producer. An output PPI measures the rate of change in the prices of products sold (outputs) as they leave the producer.

The ABS compiles a suite of quarterly input and output price indexes for selected industries of the Australian economy. As well as indexes relating to narrowly defined components of the economy (such as the Input to the House construction industry), broad based indexes are produced that cover significant parts of the economy. In particular, the "Final demand" price index covers the final stage of the measured economy. The following indexes are the major PPIs released by the ABS:

• Final demand, Producer Price Indexes, representing the final stage of production
• Input to the Coal mining industry
• Output of the Mining industries
• Input to the Manufacturing industries
• Output of the Manufacturing industries
• Input to the House construction industry
• Output of the Construction industries
• Output of the Retail Trade industry
• Output of the Accommodation and food services industries
• Output of the Transport, postal and warehousing industries
• Output of the Information media and telecommunications industries
• Output of the Rental, hiring and real estate services industries
• Output of the Professional, scientific and technical services industries
• Output of the Administrative and support services industries
• Output of the Public administration and safety industries
• Output of the Education and training industries
• Output of the Health care and social assistance industries
• Output of the Other services industries.
   

The Producer Price Indexes are used by the government and private sector for a variety of purposes:

• as deflators in the Australian National Accounts
• as a short–term indicator of inflationary trends
• for indexation in legal contracts in both the public and private sectors
• to inform business and government policy decisions
• by international organisations such as the OECD and the IMF for economic monitoring and comparison.
   

Producer Price Indexes are released each quarter (three months ending March, June, September and December). The data are released no later than 33 days after the end of the reference quarter, apart from the index of the output of the Retail Trade industry (which is released no later than 58 days after the end of the quarter).

The Producer Price Indexes measure price changes, over time, in selected industries of the Australian economy. Transactions for each of these industries may cover purchase and sales of thousands of different products at a wide variety of prices. The sheer volume and complexity of these transactions mean that a non–probability sampling method is more practicable and efficient than probability sampling methods. A non–probability sampling method involves choosing producers based on the relative importance of the products they sell or buy, who they sell to or buy from and the nature of their pricing policies.

There are two principal sources of error in surveys: sampling error and non–sampling error. Non–sampling error arises from inaccuracies in collecting, recording and processing the data. Every effort has been made to reduce non–sampling error in the PPI, by:

• careful design of questionnaires and processing systems
• providing instructions to businesses on how to price a relevant sample of producer transactions
• detailed checking of completed survey forms
• instituting a range of procedures to ensure that transactions are priced to constant quality and quantity.
   

Sampling error occurs when a sample or subset of the population is surveyed rather than the entire population. One measure of the likely difference resulting from not including all of the population in the survey is given by the standard error. While the selection of producer transactions are based on sampling techniques, standard errors are not available for the PPI. While it is reasonably straightforward to calculate sampling errors for a level estimate, it is not so straightforward to determine standard errors for the PPI which uses both sampling and index methodologies.

The main sources of ongoing price data are samples of businesses. The samples can relate to either buyers or sellers, or a combination of both. The choice is influenced by the pricing point of the index (output or input) and practical considerations such as the relative degree of concentration of buyers, and of sellers, and the implications for sample sizes and costs. Prices are collected from approximately 2,900 businesses for approximately 1,700 products. Around 25,000 individual prices are collected each quarter. Prices for most items are collected once a quarter, with the collection spread across that period. As far as possible the prices used in the indexes are actual transaction prices.

Producer Price Indexes are a key economic indicator in most countries, including Australia. The first price index of this kind compiled by the ABS (known at the time as the Commonwealth Bureau of Census and Statistics) was the Melbourne Wholesale Price Index, which was introduced in 1912 with index numbers available from 1861 and ceased in 1961. Prices were extracted from newspapers and trade publications. The next index published was the Wholesale Price Index, which was introduced in 1939, with index numbers available from 1928, and ceased in 1970. With a few exceptions, prices were obtained from Melbourne sources.

In the 1970s, the ABS introduced a number of monthly price indexes about Price Indexes of Materials Used in Manufacturing Industries, Australia (cat. no. 6411.0) and Price Indexes of Articles Produced by Manufacturing Industry, Australia (cat. no. 6412.0), Price indexes of Materials Used in Coal Mining, Australia (cat. no. 6415.0) and Price Index of Materials Used in House Building, Six State Capital Cities (cat. no. 6408.0). The frequency of these indexes changed from monthly to quarterly in the September quarter 1997. The range of price indexes published by the ABS expanded to include Producer Price Indexes for Selected Service Industries, Australia (cat. no. 6423.0) in 2000 and to include the Output of the general construction industry in Producer Price Indexes, Australia (cat. no. 6427.0) in 2002. Also in 2000, the ABS introduced an overarching, economy wide set of indexes in a Stage of Production Producer Price indexes, Australia (cat. no. 6426.0).

Starting from June quarter 2001, the publications of these individual indexes were combined in the current Producer Price Indexes, Australia (cat. no. 6427.0) publication. The index of the output of the Retail Trade industry was included from the September quarter 2013 issue, in a data series starting from 2003.

Generally, as most of the weighting patterns of the producer price indexes are derived from National Accounts Input–Output (I–O) data, these indexes are reviewed when more recent I–O data as well as other ABS data and industry information becomes available. To maintain continuous index series, the updated indexes are linked to the previous index series. The PPI are chained Lowe indexes. Item weights are currently based on the 2012–13 I–O values, using the Australian and New Zealand Standard Industrial Classification (ANZSIC), 2006 (cat. no. 1292.0).

Index numbers are released as final figures at the time they are first published. Revisions will only occur in exceptional circumstances.

Movements in indexes from one period to another can be expressed either as changes in index points or as percentage changes. Percentage changes are calculated to illustrate three different kinds of movements in index numbers:

• movements between consecutive financial years (where the index numbers for financial years are simple averages of the quarterly index numbers)
• movements between corresponding quarters of consecutive years
• movements between consecutive quarters.
   

Care should be exercised when interpreting quarter–to–quarter movements in the indexes as short–term movements do not necessarily indicate changes in trends.

The Producer Price Indexes, Australia (cat. no. 6427.0) contains Explanatory Notes that provide information about the structure, weights, data sources and other technical aspects of the series. Further information is available in Producer and International Trade Price Indexes; Concepts, Sources and Methods (cat. no. 6429.0) and Experimental Producer Price Index for the Output of the Retail Trade Industry, Australia (cat. no. 6427.0.55.007).

Detailed information, including a range of time series spreadsheets, can be found in the Data downloads section of this webpage. For links to data and publications relating to the producer price indexes and other price indexes, please see Price Indexes and Inflation.

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