Scoping the population in the Life Course Dataset

What is the Life Course Dataset population?

The Life Course Dataset population is created from administrative data sources using the Person Level Integrated Data Asset (PLIDA) and represents a series of snapshots of people in Australia at 30 June for each year from 2006 to 2021. This population has been developed as part of the pilot Life Course Data Initiative (LCDI), which aims to build an evidence base to support long-term policy responses that address disadvantage, particularly among children and their families.

The methodology for scoping the Life Course Dataset population builds on the approach developed for the Administrative Data Snapshot of Population, which was used to produce experimental population data as at 30 June 2021. This approach has been extended to cover a population snapshot at June each year from 2006 to 2021, with a particular focus on scoping the child population aged 0-14 years. This reflects the LCDI’s focus on developing data to address evidence gaps in the early years of life to better understand and respond to disadvantage.

This information paper outlines the methodological approach used to scope the Life Course Dataset population. It includes:

Key findings about the child population of the Life Course Dataset.
An overview of how the population is created from administrative data sources.
A comparison between the Life Course Dataset population and the official Estimated Resident Population, highlighting differences in scope and coverage to support appropriate interpretation of the data.

Data included in this release are not official statistics. They provide experimental information about people recorded in administrative data with particular focus on children aged 0-14 years. This release explains the methodology used to create the population of the Life Course Dataset which will serve as the basis for future releases from the Life Course Data Initiative including the experimental child-level indicator.

What is administrative data?

Children in the Life Course Dataset

At 30 June 2021, the Life Course Dataset population includes an estimated 4.8 million children aged 0-14 years living in Australia.
The number of children in the Life Course Dataset population has increased steadily from 2006 to 2021, growing at an average annual rate of 1.2%, compared to 1.6% for the total population.
The number of children as a proportion of the entire population has decreased over this period, from 19.6% in 2006 to 18.5% in 2021.

Children in the Life Course Dataset, 2006-2021
	Number of children ('000)	Proportion of total population (%)
Jun-06	4,004.3	19.6
Jun-07	4,058.7	19.4
Jun-08	4,107.9	19.3
Jun-09	4,157.4	19.2
Jun-10	4,198.7	19.1
Jun-11	4,238.2	19.0
Jun-12	4,314.7	19.0
Jun-13	4,392.1	19.0
Jun-14	4,462.5	19.0
Jun-15	4,521.8	19.0
Jun-16	4,588.1	19.0
Jun-17	4,652.4	18.9
Jun-18	4,703.6	18.9
Jun-19	4,747.8	18.8
Jun-20	4,776.1	18.6
Jun-21	4,783.2	18.5

Children in the Life Course Dataset, 2006-2021

["","Number of children","Proportion of total population"]

[["Jun-06","Jun-07","Jun-08","Jun-09","Jun-10","Jun-11","Jun-12","Jun-13","Jun-14","Jun-15","Jun-16","Jun-17","Jun-18","Jun-19","Jun-20","Jun-21"],[[4004.31],[4058.7],[4107.87],[4157.4],[4198.69],[4238.2],[4314.68],[4392.1],[4462.47],[4521.81],[4588.05],[4652.42],[4703.55],[4747.76],[4776.06],[4783.17]],[[19.63500258],[19.38739841],[19.29922183],[19.16714576],[19.07277421],[19.00154929],[18.98721627],[18.99437028],[18.99139303],[18.98035913],[18.97786702],[18.94573095],[18.87678849],[18.77328567],[18.59999498],[18.45719508]]]

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Data used to create the Life Course Dataset population

The Life Course Dataset population is created using integrated administrative data from the Person Level Integrated Data Asset (PLIDA). PLIDA is a secure data asset combining information on health, education, government payments, income and taxation, employment, and population demographics to create a comprehensive picture of Australia over time.

Population scoping for the Life Course Dataset is undertaken using the Core Scoping module within PLIDA. This module enables users to determine an approximate resident population for a given point in time, based on a structured methodology developed by the ABS as part of the Administrative Data Snapshot of Population.

The Core Scoping module is created by combining information from a range of different administrative datasets and consists of three components:

Vitals table

Datasets used to create the vitals table in the Core Scoping module
Dataset	Data availability
ATO Client Register (ATO CR)	1 Jul 1999 to 30 Jun 2024
Medicare Consumer Directory (MCD)	1 Jan 2006 to 30 Jun 2024
DOMINO Centrelink Administrative Data (DOMINO)	1 Jan 2006 to 30 Sep 2024
Death registrations	1 Jan 2007 to 31 Dec 2023

Residence tables

Activity tables

Datasets used to create the activity tables in the Core Scoping module
Dataset	Data availability
Income Tax Return (ITR)	1 Jul 2000 to 30 Jun 2023
Payment Summary (PS)	1 Jul 2002 to 30 Jun 2023
DOMINO Centrelink Administrative Data (DOMINO)	1 Jan 2006 to 30 Sep 2024
Medicare Benefits Schedule (MBS)	1 Jan 2006 to 30 Sep 2024
Pharmaceutical Benefits Scheme (PBS)	1 Jan 2006 to 30 Dec 2024
Australian Immunisation Register (AIR)	1 Jan 2011 to 31 Dec 2024
Single Touch Payroll (STP)	1 Jan 2020 to 30 Jun 2024

Creating an ever-resident administrative population

To build the Life Course Dataset population, the first step is to create what we call the ever-resident administrative population.

This population is created from the PLIDA Person Linkage Spine, which uses data linkage methods to bring together records from the Medicare Consumer Directory (MCD), DOMINO Centrelink administrative data (DOMINO) and Personal Income Tax data (PIT).

Anyone who has appeared in at least one of these datasets since 2006 is included in the ever-resident population. The aim is to cover all people who were living in Australia at any time from 2006 onwards. At 30 June 2021, the ever-resident administrative population included around 39 million people.

Scoping the population at a point in time

To create the Life Course Dataset population, the next step is to determine which people in the ever-resident population were living in Australia at the reference date of 30 June for each year from 2006 to 2021.

This process, known as scoping, applies a series of rules to align the ever-resident population with the concept of the Estimated Resident Population (ERP). The ERP includes all people who usually live in Australia, including those temporarily overseas, and excludes short-term visitors. The image below shows the scoping process.

Scoping the PLIDA ever-resident population to the Life Course Dataset population at a point in time

Image

Description

The image is a flow diagram scoping the Life Course Dataset population from the ever-resident population in PLIDA.

There are three main boxes in the diagram. The first box on the left represents the ever-resident Australian population (the PLIDA Spine population). The PLIDA Spine population includes anyone who has appeared at least once in either the Australian Taxation Office, Centrelink or Medicare datasets from 2006 onwards.

Data from the left hand box feeds into the centre box, which represents the rules to determine individuals living in Australia on the reference date, 30 June of each year, using birth, death, migration, and activity information. For each year, people are removed from the scoped population if they: died before 30 June, were born after 30 June, were not in Australia for at least 12 months within the 16 months following 30 June, had no activity in the last 1, 2 or 5 years (depending on age) before 30 June or, are older than 115 years on 30 June.

This scoped population data feeds into the final box on the right hand side, showing the replication of the scoping process annually to produce a population snapshot for each year from 30 June 2006 to 30 June 2021.

Scoping ensures the administrative population reflects ERP by removing individuals who are unlikely to have been residing in Australia at the reference date. These rules are applied in a specific order, as summarised in the table below for the 30 June 2021 snapshot.

Rules used to scope the administrative data to people living in Australia at 30 June 2021
Scoping rule	Measured by	Number of people removed
Remove if died before the reference date	Date of death	4.6 million
Remove if born after the reference date	Date of birth	0.8 million
Remove if not in Australia for 12 of the subsequent 16 months on the reference date	Date of arrival Date of departure	4.6 million
Remove if no activity in the last 1, 2 or 5 years before the reference date depending on age	Use of government services in the last 1 to 5 years*	3.0 million
Remove if older than 115 years on the reference date	Date of birth	237 people

*5 years for ages 1–24, 2 years for ages 25–79, and 1 year for ages 80 and over.

Removing records for death before or birth after reference date

Accounting for overseas migration

Applying age-based activity rules

Individuals with no recorded interaction with government services within a defined time frame are assumed to have either died or left Australia, even if no death or migration record is available.

The time frame varies by age:

Aged 1–24 years: no activity in the past 5 years.
Aged 25–79 years: no activity in the past 2 years.
Aged 80 years and over: no activity in the past 1 year.

These thresholds account for differences in how frequently people of different ages interact with government services. Younger individuals are generally less likely to engage with services regularly, while older individuals tend to have more frequent interactions. No activity rule is applied to 0-year-olds, due to expected delays in birth registration with Medicare.

Due to limited administrative data in PLIDA prior to 2006, activity-based scoping rules are adjusted for earlier years to avoid excluding individuals solely because of data availability. If a person is excluded in an early year (2006 to 2010) for not meeting the age-specific activity threshold, but is considered in scope in a later year when sufficient data becomes available, then they are retrospectively treated as in scope for the earlier year(s).

This is applied as follows:

Aged 1–24 years: if excluded between 2006 and 2010 for not meeting the 5-year activity rule, but in scope in 2011, they are retrospectively included for years 2006 to 2010.
Aged 25–79 years: if excluded in 2006 or 2007 for not meeting the 2-year rule, but in scope in 2008, they are included for 2006 and 2007.
Aged 80 years and over: if excluded in 2006 for not meeting the 1-year rule, but in scope in 2007, they are included for 2006.

These adjustments are made to ensure the scoped population, particularly children, is of higher quality and more closely aligned with the Estimated Resident Population (ERP). By retrospectively including individuals who later meet activity thresholds, we reduce the risk of undercoverage due to early data limitations and improve the robustness of child population estimates.

How the Life Course Dataset population compares to official population estimates

The Life Course Dataset population is an experimental product that uses integrated administrative data to provide a snapshot of Australia’s population at 30 June of each year from 2006 to 2021. It does not replace Australia’s official population estimates, the Estimated Resident Population (ERP).

The Life Course Dataset population is constructed from administrative data. Administrative data is not typically designed with statistical production in mind. Hence, there are some characteristics of the data that should be considered when interpreting the Life Course Dataset population.

To help users understand this complexity, different factors affecting the interpretation of the Life Course Dataset population are explained through comparison to ERP below.

At the national level, the Life Course Dataset population closely aligns with ERP for each year from 2006 to 2021. The largest difference occurs in the 30 June 2021 snapshot, where the Life Course Dataset provides a higher estimate of the population by approximately 229,520 people, which is 0.9% higher than ERP. This higher estimate is likely due to the inclusion of Single Touch Payroll (STP) data in 2020, which increased the volume of administrative activity in the PLIDA data, and may have inflated counts of individuals for inclusion in the Life Course Dataset population.

Life Course Dataset population and ERP, Australia, 2006-2021
	Life Course Dataset population ('000)	ERP ('000)
Jun-06	20,393.7	20,451.0
Jun-07	20,934.8	20,827.6
Jun-08	21,285.1	21,249.2
Jun-09	21,690.2	21,691.7
Jun-10	22,014.0	22,031.8
Jun-11	22,304.5	22,340.0
Jun-12	22,724.1	22,733.5
Jun-13	23,123.2	23,128.1
Jun-14	23,497.3	23,475.7
Jun-15	23,823.6	23,816.0
Jun-16	24,175.8	24,190.9
Jun-17	24,556.5	24,592.6
Jun-18	24,917.1	24,963.3
Jun-19	25,290.0	25,334.8
Jun-20	25,677.8	25,649.3
Jun-21	25,914.9	25,685.4

Life Course Dataset population and ERP, Australia, 2006-2021

["","Life Course Dataset population","ERP"]

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The age distribution of the Life Course Dataset population closely aligns with ERP across most age groups. For the majority of ages, differences between the two measures are relatively small, usually within a few percentage points.

Age distribution of Life Course Dataset population and ERP, Australia, 30 June 2021
Age	Life Course Dataset population ('000)	ERP ('000)
0	309.9	298.8
1	301.4	294.9
2	306.9	301.0
3	309.3	303.5
4	317.1	310.8
5	326.0	320.9
6	323.0	319.2
7	326.1	323.2
8	330.0	326.7
9	324.4	326.4
10	320.3	324.6
11	323.3	328.2
12	322.4	325.0
13	322.9	324.8
14	320.1	321.0
15	308.1	308.3
16	298.3	297.4
17	293.3	291.8
18	291.4	288.9
19	294.4	292.8
20	307.8	309.1
21	319.6	320.2
22	323.5	323.0
23	330.9	329.5
24	343.6	341.2
25	352.8	351.4
26	367.1	362.9
27	370.1	365.4
28	374.4	369.0
29	376.5	372.9
30	383.5	381.9
31	388.8	383.9
32	382.7	379.5
33	381.7	377.1
34	380.5	376.8
35	381.1	379.4
36	382.2	377.8
37	379.4	374.4
38	378.7	373.7
39	367.6	361.8
40	355.7	352.5
41	344.0	335.5
42	335.8	328.5
43	328.6	319.9
44	324.4	318.0
45	323.6	318.7
46	328.9	322.0
47	333.5	327.4
48	341.4	334.9
49	353.5	347.0
50	354.1	350.1
51	332.4	327.0
52	328.3	322.5
53	313.8	309.4
54	306.8	302.8
55	304.1	301.8
56	306.7	305.2
57	315.8	313.4
58	317.6	316.7
59	313.9	313.8
60	308.2	310.6
61	297.9	299.1
62	293.2	292.9
63	285.1	285.4
64	276.9	277.6
65	270.4	271.0
66	263.3	262.3
67	255.3	254.1
68	252.4	250.5
69	243.8	242.5
70	238.3	238.7
71	234.9	233.2
72	225.4	224.7
73	223.5	223.5
74	232.5	226.7
75	185.3	186.5
76	177.5	175.2
77	166.3	162.9
78	144.9	144.0
79	140.7	138.7
80	127.8	125.7
81	119.9	118.4
82	111.6	109.7
83	101.9	100.1
84	93.5	91.6
85	82.9	81.6
86	73.6	71.9
87	64.6	63.3
88	57.5	56.6
89	50.3	49.9
90	45.7	45.0
91	39.1	38.8
92	31.7	31.6
93	25.8	25.7
94	19.8	19.9
95	15.2	15.8
96	11.3	11.6
97	8.1	8.1
98	5.5	5.5
99	3.8	3.7
100+	5.9	5.3

Age distribution of Life Course Dataset population and ERP, Australia, 30 June 2021

["Age","Life Course Dataset population","ERP"]

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There are some exceptions to the close alignment between the Life Course Dataset population and ERP across age groups.

The Life Course Dataset population overestimates the number of infants aged 0 years across all years from 2006 to 2021 by approximately 11,140 infants, which is 3.7% higher than ERP. This overestimate is due to challenges in applying age-based activity scoping rules for infants in the administrative data.

At older ages, particularly among those aged 90 years and over, the Life Course Dataset also tends to produce a higher estimate than the official population. This reflects the nature of administrative data, where individuals are often retained in scope unless a recorded date of death is available, or they are aged over 115 years, in which case they are excluded from the dataset to maintain data quality.

APA

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