About the complete monthly CPI design

The CPI is a critical economic indicator underpinning decisions that impact all Australians. Australia is currently one of only two Organisation for Economic Co-operation and Development (OECD) economies and the only G20 country that does not produce a complete monthly measure of CPI.

The introduction of a complete monthly CPI will significantly enhance decision-making for both government and the Reserve Bank of Australia, providing them with more precise and timely data to inform fiscal and monetary policies. It will facilitate the generation of more granular data, encompassing each capital city, and detailed expenditure groups. This expanded dataset will provide deeper insight into the drivers of inflation, an enhanced understanding of cost-of-living pressures nationwide. 

Stakeholders were actively engaged in providing input on crucial aspects of the CPI publication design during a public consultation held in late 2023. The key design features of the complete monthly CPI, along with a summary of stakeholder feedback are available on the ABS Consultation Hub.  

The public consultation was informed by a preliminary Discovery Stage conducted in October 2023. During this stage, the ABS directly engaged with State and Federal government agencies, academics, financial market operators and CPI experts to glean insights into their priorities and lay the groundwork for the initial CPI design.  

The complete monthly CPI will be published in late 2025. It will be released four weeks after the reference period, with a focus on prioritising accuracy and comprehensive data coverage. The publication will include detailed commentary, analysis, and data tables consistent with the current quarterly CPI series. 

The ABS will continue to maintain the existing quarterly series and publish this data, every third month. Learn more about the concepts, data sources and methods used to compile the quarterly CPI. 

Collection of prices for the CPI is different to standard survey sampling with prices collected through a range of different approaches. To produce a complete monthly measure of CPI, the ABS will need to increase collection of information from businesses through phone and internet collection, private sector datasets (transactions and administrative data) and automated collection from websites (web-scraping). 

Commencing April 2024, the ABS has increased the frequency of prices data collected directly from businesses. This is the fastest, most reliable approach to deliver the additional data needed to create a complete monthly measure of CPI. The increase in collection frequency to a monthly cadence for those businesses currently reporting quarterly will place some additional reporting burden on business but is necessary to meet a late 2025 delivery timeframe.   

The ABS is committed to collecting information efficiently while minimising the burden on data providers. To achieve this, the ABS will work with data providers to devise additional data collection methods and explore new sampling techniques and expanded use of new technologies, all aimed at reducing the burden on providers.  

Big data acquired from the private sector, such as transactions data, will also be used to substitute for direct collected data. For example, the ABS uses supermarket scanner data for the CPI food category. Over time, the ABS will reduce the additional burden on business, and enhance the quality of the complete monthly measurement of the CPI, by negotiating the acquisition of private sector datasets.

The ABS will commence publication of the complete monthly measure of CPI in late 2025. The first release will occur approximately four weeks after the end of the reference month, on a Wednesday. Further details regarding the release schedule will be provided on the ABS website around mid-2025, closer to the publication release date.

In October 2022, the ABS introduced the publication of a monthly CPI indicator, marking a significant advancement to increase the frequency of inflation data compared to the traditional quarterly CPI release.  

The monthly indicator offers a valuable and more timely assessment of inflation. However, as only between 66 and 77 per cent of the CPI basket of goods and services are updated in any given month, the ABS considers it an ‘indicator’ rather than a complete monthly measure of CPI inflation.

The eventual replacement of the monthly CPI indicator with a complete monthly CPI measure will provide more granular information, enabling deeper insights and analysis of inflation’s impacts on households and the economy.

Read more about the Monthly Consumer Price Index Indicator.

The current CPI quarterly series will be available to maintain continuity for widely used indexation arrangements and time series analysis.   

With the advent of the complete monthly CPI, the quarterly series will be derived based on the average of the three months within each quarter. Detailed information outlining adjustments to the quarterly time series will be communicated to stakeholders closer to the publication release date of the complete monthly CPI. 

For further insights into the methodology behind the CPI quarterly data series, explore our resources.

The intended monthly CPI design includes data published at the national level, derived as a weighted average of the eight capital cities. This comprises:

• headline CPI
• the eleven CPI groups, as well as sub-groups (33)
• expenditure classes (87) for each capital city.
• contribution to annual and monthly percentage change to the All groups CPI.

Index numbers published to two decimal places and movements will be presented to one decimal place. Data will only be revised in exceptional circumstances, such as to correct a significant error, in line with the standard practice for CPI. 

In the initial phase, a limited number of seasonally adjusted series will be published during the first two years, primarily due to some monthly time series being shorter than the length required for standard seasonal adjustment. 

The ABS is actively investigating the quality of trimmed mean and weighted median measures in cases where certain expenditure classes cannot be seasonally adjusted using conventional methods. Additional information regarding these methodologies will be made available prior to publication.