3302.0.55.003 - Life Tables for Aboriginal and Torres Strait Islander Australians, 2010-2012  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 15/11/2013   
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APPENDIX 2 ESTIMATING REVISED LIFE EXPECTANCY MEASURES FOR 2005–2007


INTRODUCTION

In 2008, the Council of Australian Governments (COAG) agreed to six ambitious targets to help remove some of the disadvantages faced by Aboriginal and Torres Strait Islander Australians. One of these targets was to close the gap in life expectancy within a generation (by 2031). The estimates of Aboriginal and Torres Strait Islander and non-Indigenous life expectancy are used to measure progress against this indicator. For this reason it is important that the ABS provides comparable estimates over time, as far as possible.

However, the ABS also commits to providing the most accurate measure of life expectancy using the best available data and methodologies. Two improvements (detailed below) have been made for the official 2010-2012 Aboriginal and Torres Strait Islander life tables and so a comparative set of 2005-2007 life tables has been compiled in order to be able to effectively measure the change in life expectancy over time.

It must, however, be recognised that the people identified as Aboriginal and Torres Strait Islander in one Census to the next will be slightly different populations. This is particularly true for the 2006 and 2011 Census where the population identified increased by 21%. For more information, see Census of Population and Housing: Understanding the Increase in Aboriginal and Torres Strait Islander Counts, 2006-2011 (cat. no. 2077.0).


Changes to 2010-2012 life table methodology

Two improvements made to the data and methodology have affected the comparability of the 2010-2012 estimates with the 2005-2007 estimates released previously.

The first improvement was only able to be made at the Australia level and only affects the headline national estimates. Age-specific identification rates were included in the calculation of the adjustment used to enhance the numbers of Aboriginal and Torres Strait Islander deaths to account for underidentification in death registrations. For more information, see Chapter 3: Data linkage to derive Aboriginal and Torres Strait Islander deaths identification rates.

The other improvement, affecting all estimates, was an improvement to the Post Enumeration Survey (PES) methodology and procedures. This has affected both the underlying population estimates and the propensities used to estimate identification of Aboriginal and Torres Strait Islander deaths. For further information on the changes to methodology and procedures in the PES, see Census of Population and Housing - Details of Undercount, 2011 (cat. no. 2940.0).


Estimating the statistical impact on 2010-2012 life expectancy

After each Census, the ABS destroys all source data relating to the Census, including data from the Census to Deaths linkage study. For this reason, the 2005-2007 life tables are unable to be recalculated directly. In order to determine a comparable set of life tables for 2005-2007, the statistical impact of the improvements for 2010-2012 was calculated and applied to the previously released 2005-2007 life expectancy estimates.

To determine the statistical impact of the two improvements mentioned above, a comparative set of 2010-2012 life tables was calculated. This set was produced without the age-specific adjustment in order to assess the impact of the improved methodology for the headline Australian estimates. To remove the impact of the change in PES methodology, the comparative set of life tables also used the 2006 PES propensities (i.e. P(ATSI/ATSI), P(ATSI/NI) and P(ATSI/NS)) and also made an allowance for the PES contribution to estimated resident population data.

A comparison of the headline 2010-2012 life expectancy estimates and the comparative set are presented in table A2.1.

A2.1 ABORIGINAL AND TORRES STRAIT ISLANDER LIFE EXPECTANCY, Headline and Comparison Estimates - 2010-2012

2010-2012 ESTIMATES
2010-2012 COMPARISON ESTIMATES
DIFFERENCE(a)
Males
Females
Males
Females
Males
Females
Males
Females
years
years
years
years
years
years
%
%

NSW
70.5
74.6
72.1
75.6
-1.6
-1.0
-2.3
-1.4
Qld
68.7
74.4
69.9
75.4
-1.2
-1.0
-1.8
-1.3
WA
65.0
70.2
65.5
70.6
-0.5
-0.4
-0.8
-0.5
NT
63.4
68.7
63.4
68.5
-
0.2
-
0.3
Aust.(b)(c)
67.4
72.3
68.8
73.5
-1.5
-1.2
-2.2
-1.7
Headline Aust.(c)(d)
69.1
73.7
68.8
73.5
0.3
0.2
0.4
0.2

- nil or rounded to zero (including null cells)
(a) Based on unrounded estimates.
(b) These estimates are not the headline estimates for Australia, because they are calculated without an age-adjustment, but are provided to enable effective comparison with the state and territory, and remoteness area estimates.
(c) Includes all states and territories.
(d) Headline estimates for Australia are calculated using an improved methodology (taking into account age-specific identification rates) that could not be applied at the state and territory or remoteness area levels. Therefore this data should not be compared with data for any state or territory, or remoteness area.



Revised 2005-2007 estimates

Comparative life expectancy estimates for 2005-2007 were obtained by applying the relative statistical impacts to the estimates of life expectancies for Aboriginal and Torres Strait Islander Australians that were previously released. These estimates were in turn used to determine the adjusted Aboriginal and Torres Strait Islander deaths, enabling the estimation of non-Indigenous deaths and the non-Indigenous life expectancy at birth.

Comparative life expectancy estimates for Aboriginal and Torres Strait Islander Australians, non-Indigenous Australians and the revised gap in life expectancy for 2005-2007 are presented in table A2.2


Estimate of change in life expectancy over the 5 years with revised 2005-2007 data

The revised 2005-2007 life expectancy estimates make it possible to examine the change in life expectancy over time and estimate the resulting change in the gap in life expectancy between Aboriginal and Torres Strait Islander and non-Indigenous Australians. Table A2.2 shows the revised life expectancies for 2005-2007 and the current estimates for 2010-2012. At the national level, the gap in life expectancy has improved from 11.4 years for males and 9.6 years for females in 2005-2007 to 10.6 years and 9.5 years respectively in 2010-2012.

A2.2 ABORIGINAL AND TORRES STRAIT ISLANDER AND NON-INDIGENOUS LIFE EXPECTANCY, Revised 2005-2007 estimates and official 2010-2012 estimates

ABORIGINAL AND TORRES STRAIT ISLANDER
NON-INDIGENOUS
DIFFERENCE BETWEEN NON-INDIGENOUS AND ABORIGINAL AND TORRES STRAIT ISLANDER LIFE EXPECTANCY AT BIRTH(a)
Males
Females
Males
Females
Males
Females
years
years
years
years
years
years

REVISED 2005-2007 ESTIMATES

NSW
68.3
74.0
78.8
82.6
10.5
8.6
Qld
67.1
72.7
78.8
82.7
11.8
10.0
WA
64.5
70.0
79.2
82.9
14.7
12.9
NT
61.5
69.4
75.5
81.0
14.0
11.6
Aust.(b)(c)
65.7
71.7
78.9
82.7
13.1
11.0
Headline Aust.(c)(d)
67.5
73.1
78.9
82.6
11.4
9.6

2010-2012 ESTIMATES

NSW
70.5
74.6
79.8
83.1
9.3
8.5
Qld
68.7
74.4
79.4
83.0
10.8
8.6
WA
65.0
70.2
80.1
83.7
15.1
13.5
NT
63.4
68.7
77.8
83.1
14.4
14.4
Aust.(b)(c)
67.4
72.3
79.8
83.2
12.4
10.9
Headline Aust.(c)(d)
69.1
73.7
79.7
83.1
10.6
9.5

(a) Based on unrounded estimates
(b) These estimates are not the headline estimates for Australia, because they are calculated without an age-adjustment, but are provided to enable effective comparison with the state and territory, and remoteness area estimates.
(c) Includes all states and territories.
(d) Headline estimates for Australia are calculated using an improved methodology (taking into account age-specific identification rates) that could not be applied at the state and territory or remoteness area levels. Therefore this data should not be compared with data for any state or territory, or remoteness area.