City of Perth

Economic model updates

Many of the datasets within this economic profile are underpinned by the NIEIR-ID economic model that is updated each financial year. In each update, you can expect to see differences in some of the numbers to previous updates. This is particularly true for recent historical data related to Gross Regional Product, Value-added for some industries, and Local Jobs.

Why has historical data changed?

We regularly update our economic models to ensure they reflect the latest data and economic conditions. This provides you with the most accurate and reliable information for informed decision-making.

While these revisions may affect historical data consistency, we clearly communicate the changes made, their impact, and the rationale behind them.

Here are the key reasons for the revisions:

  • New data: Our annual update incorporates information from various sources, including the latest 2020-2021 Input-Output table, providing a clearer picture of local economies.
  • Data source revisions: Revisions by the Australian Bureau of Statistics (ABS) to key inputs like labour force and population estimates have necessitated model
  • Inflation adjustments:For datasets measuring economic activity (e.g., industry value added), we remove price change effects using the Consumer Price Index (CPI). This price base update requires historical data revisions for all related financial data.
  • Methodology enhancements: Changes in economic data calculation methods can sometimes lead to revisions.

These improvements enable a more accurate understanding of changes in local economies, which in turn facilitates the development of more effective policies to promote economic recovery and growth.

What was the nature of the revisions in the latest release?

New data

The annual data update incorporates information from various sources. Key sources and their respective release dates are provided below for reference:

  • Australian 2020-2021 Input-Output Table – Released in 2023
  • ABS National Accounts in $2022CVM – December 2023
  • ABS State Accounts in $2022CVM – November 2023
  • Australian Industry (8155) in $2022CVM – May 2023

Inflation adjustments

From one period to another the quantities and prices comprising transactions in the economy change. This means that when the current price value of an aggregate, such as GRP or value added, in one period is compared with the current price value in another period, the difference between them usually reflects both changes in quantity and changes in price. In order to estimate by how much the 'volume' of GRP has changed between the two periods we need to exclude the direct effects of price change.

The price base used for the 2023 Update is the same as that incorporated in the $2022 CVM (Chain Volume Measures), reflecting the price changes initially observed in the National Accounts of December 2022, with similar adjustments appearing in the State Accounts around that period. This adjustment corresponds to an approximate 8.0% increase in Value Added for the corresponding period.

Data source revisions

Labour force revisions

The most significant revision to the input data sources was the Small Area Labour Market data (SALM). For example, a comparison of the 2022 data from the Small Area Labour Market data (SALM) publications of June 2023 and June 2022 shows that the average absolute LGA shift in labour force estimates for the 2022 year in the SALM data was 3% across all LGAs. Some regions shifted by as much as 14%.

Similarly a quick look at the ANZSIC employment data from the Labour force survey indicates that, between editions, values for the 2022 year at the national, ANZSIC Division (1D) level showed an absolute change of 3.4% (10,000 employed) for Agriculture, Forestry and Fishing, and almost 3% (8,000 employed) for Mining. At the state level with more detailed industry classification the percentage swing between editions can be greater.

ATO Taxation Statistics and ABS Industry

Other data sources, such as the taxation statistics and the ABS Australian Industry data are usually one or two years behind the current date. This year's update utilised ATO data from the 2020-21 tax year. This provided improved structure for our regional modelling for the 2021 year onwards, which results in revisions to the dependent values, for those years and the following years.

Input-Output Utilisation

The model utilises national Input-Output (IO) tables to help build input-output relationships for specific regions across Australia. This is an important step in estimating inter-regional trade flows. Revising input-output relationships each year is necessary to reflect potential changes in supply chain relationships. The release of the 2021/22 National IO Tables did not happen in time to be incorporated into the NIEIR-ID economic model and therefore 2020/21 tables have been used.

Methodology enhancements

This year's update was specifically aimed at enhancing data stability. The main improvements were:

  • The model has been adjusted to prioritise census data in cases where discrepancies exist between ABS Labour force data and census data. The areas most impacted were Regional Cities where labour force data was inconsistent with ABS Census data.
  • The model has been improved to better address missing place of work data from the ABS Census.

City of Perth

economic profile