The basic structure of I-O and associated tables, special treatments adopted in compiling I-O tables, and using I-O tables for analysis are shown in Australian System of National Accounts: Concepts, Sources and Methods, Chapter 22, Input-Output Tables.

The I-O tables are formatted in millions of dollars.

### Additivity

The sum of the components may not equal the reported total in all cases. This has been caused by small values (less than $500,000) being assigned to different industries or products as part of the modelling processes used in the compilation of I-O tables. Cells with a value of less than $500,000, while not displayed in the tables, have been included in the total values. The totals reported for both the Input-Output Tables and the Input-Output Tables (Product Details) published in the Australian National Accounts: Input-Output Tables are related and sum to the same values. Data in some Excel spreadsheets contain additional decimal places to facilitate loading into some analysts modelling applications.

### Impact of small value modelling

Some modelling techniques are used to balance and populate the tables, particularly where directly collected information is not available for every cell. Consequently, very small values may be estimated in certain cells and the statistical accuracy of this data cannot be verified. Where values less than $1 million are shown, they solely facilitate reconciliation, row and column balancing and do not carry any economic meaning.

### Confidentiality

The ABS collects data from individuals and organisations as a routine part of statistical compilation. There is a legal and ethical responsibility for the ABS to respect and maintain the secrecy, privacy and protect the identity of those providing statistical information.

The information contained in the I-O tables has been confidentialised via three methods:

- Data suppression
- Data perturbation
- Collapsing row or column categories

Data suppression is the main method used to confidentialise the I-O tables, which involves hiding the value of certain cells in a table with "n.p" notation (not published). Where values have been suppressed, they are still included in totals where appropriate.

A small number of data points in the I-O tables are confidentialised via the process of data modification (perturbation), which involves altering a cell value to provide confidentiality protection, while maintaining as much data utility as possible. This technique ensures that row and column totals can be published and are fully additive.

Confidentiality has also been applied through the combination of Input-Output Industry Groups (IOIGs) and Input-Output Product Groups (IOPGs) 1203 and 1204 into 1205. In addition, Brown coal (IOPC 06000020) has been collapsed into black coal (IOPC 06000010) in the 2020-21 tables.

More information on the ABS’ confidentiality framework, and treatments, can be found in the ABS Confidentiality Series.

### Departures from 2008 System of National Accounts

I-O tables depart from the 2008 System of National Accounts (SNA08) and from the rest of the Australian national accounts in one main respect, namely the definition of output at basic prices. The departure relates to the treatment of charges incurred in moving goods from their point of production to the final user, where no separate charging or invoicing has occurred. These delivery arrangements, relating to delivery by a third party operator arranged by the producer and paid for by the producer and not separately charged to the end user, are considered transport margin activity in the I-O tables. This treatment differs to that prescribed in SNA08.

Under the 1968 version of the System of National Accounts (SNA68) these charges were excluded from the basic price valuation of the good concerned while under the SNA08 treatment the basic price valuation of the good includes these delivery charges. The ABS considers that the change in definition was inappropriate from an analytical point of view and would result in the same product being valued differently depending on whether or not the producer charged separately for the delivery of the product. The ABS therefore applies an adjustment to the I-O tables to reallocate delivery charges separably invoiced to transport, so they are included in transport margins and reduce basic prices.

In the 2020-21 I-O tables, the value of this adjustment is $46.6b. It is applied to industries and products in agriculture, mining and manufacturing and modelled based on questions on collection forms about invoicing arrangements and transport expenses.