1. Calculate estimates across income types per PLIDA data source for linked records

This step involves the calculation of admin incomes from:

• Data Over Multiple Individual Occurrences (DOMINO)
• Single Touch Payroll (STP)
• Payment Summary (PS)
• Income Tax Return (ITR)
• Superannuation Account Extract (SAE)

Some admin sources can be used to estimate multiple income types.

These calculations are performed on linked people aged 15 years and over for the SIH 2019-20 and Census 2021, considered separately. (That is, the sample may differ between SIH and Census.) Linked records refer to data available for people who are associated with a unique PLIDA spine ID. For both SIH and Census, there are a small number of instances where the spine ID is associated with more than one record. These people are not deemed as linked. 

The linkage rates for people aged 15 years and over are:

• 89% for SIH 2019-20 (weighted percentage).
• 93% for Census 2021 (excluding imputed people and overseas visitors).

Linkage rates are important to consider as there may be characteristics of people without linkage that affect how the data represents the total population. 

• Further details of the SIH sample linkage are discussed in the SIH estimate compilation summary.
• For Census, age and labour force information for people without a linkage are presented in Table 3 in the results summary.

For SIH, the reference period for both annual and current income estimates is 2019-20. The date of household interview is used as a reference date in estimating a person’s current income. 

For Census, the reference period for annual estimates is 2020-21, while current (weekly) income estimates relate to 10 August 2021.

For each data source, the specific PLIDA Modular Product tables and key data items used in calculating income types from each source are provided. Accompanying each data item is a description of its role in the income calculation. These descriptions are explained below:

• Determines selection interval. The item determines the interval of time used for the creation of an income estimate.
• Establishes income amounts. The item is used to identify or confirm relevant income amounts.
• Distinguishes instances. The item helps ensure that each instance of an event or item is measured e.g. each job for multiple job holders.
• Checks validity. The item checks the validity of a current income calculated from using another admin source.
• Determines income received. The item helps to determine the income amount received.