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2077.0 - Census of Population and Housing: Understanding the Increase in Aboriginal and Torres Strait Islander Counts, 2006-2011 Quality Declaration 
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 17/09/2013  First Issue
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TECHNICAL NOTE 2 PEOPLE FOR WHOM INDIGENOUS STATUS IS UNKNOWN

PEOPLE FOR WHOM INDIGENOUS STATUS IS UNKNOWN

1 Despite the best efforts of the Australian Bureau of Statistics (ABS) to collect complete information from all people in Australia on Census night, there will always be a group of people for whom Indigenous status is not known. While some people with an unknown Indigenous status will be Aboriginal and/or Torres Strait Islander people, and some will be non-Indigenous people, the exact proportions cannot be determined from the Census data. This complicates analysis of Census counts, given Indigenous status is not imputed within Census information, but is instead imputed later within the Post Enumeration Survey for use in producing population estimates. (Imputation is a statistical process for predicting values where no response was provided to a question and a response could not be derived.)

2 The number of Census records with an unknown Indigenous status in the 2011 Census was 1,058,600 (5% of the total Census count) compared with 1,133,400 records (6% of the total Census count) in 2006. The difference of 74,800 records represents a 7% decrease in records with an unknown Indigenous status between the 2006 and 2011 Censuses. This means that more people had a known Indigenous status in 2011 than in 2006, and this may account for some of the 'unmeasurable' increase in Census counts of Aboriginal and Torres Strait Islander people between 2006 and 2011.

3 The Northern Territory had the highest proportion of records with an unknown Indigenous status in 2011 (8%), followed by Western Australia (6%) and Queensland and New South Wales (both 5%). Between the 2006 and 2011 Censuses, the proportion of records with an unknown Indigenous status fell in all states and territories, with the largest reductions observed in New South Wales (down 1.0 percentage point), followed by Tasmania (down 0.9 percentage points) and Victoria (down 0.8 percentage points).


INDIGENOUS STATUS UNKNOWN(a), by proportion of state/territory(b)

2006
2011
Change
no.
%
no.
%
% points

New South Wales
391 274
6.0
342 923
5.0
-1.0
Victoria
266 028
5.4
246 893
4.6
-0.8
Queensland
224 909
5.8
224 206
5.2
-0.6
South Australia
69 318
4.6
62 934
3.9
-0.7
Western Australia
127 328
6.5
130 719
5.8
-0.7
Tasmania
22 903
4.8
19 380
3.9
-0.9
Northern Territory
16 505
8.6
17 391
8.2
-0.4
Australian Capital Territory
15 025
4.6
14 005
3.9
-0.7
Australia(c)
1 133 446
5.7
1 058 586
4.9
-0.8


(a) Usual residence Census counts. Excludes overseas visitors.
(b) Proportions are based on total population for each state/territory.
(c) Includes
Other Territories.
Note: Totals and components may not be consistent within and between tables due to introduced random error to protect confidentiality of Census respondents - see Census Dictionary, 2011 (cat. no. 2901.0).


4 There are two broad situations which result in a person’s Indigenous status being unknown:
  • the returned Census form does not have a response to the Indigenous status question (known as item non-response), or
  • when no Census form is received from a dwelling the number of males and females and other key demographic variables are imputed. Indigenous status is not imputed for these records, but is coded to 'not stated'.
5 In non-private dwellings, a nominated person completes a summary Census form that lists all people staying there, and personal Census forms (which include the Indigenous status question) are distributed to each person on the summary form. If personal forms are not returned or not completed for all individuals listed on the summary form, the Indigenous status for these people is unknown. People in non-private dwellings accounted for 11% of people with an unknown Indigenous status in 2011. Nationally, people living in non-private dwellings were about three times more likely to have an unknown Indigenous status than people in private dwellings (16% compared with 5%). There was some variation by state and territory. For example, in the Australian Capital Territory, people living in non-private dwellings were about five times more likely to have an unknown Indigenous status than those living in private dwellings (17% compared with 3%) while in the Northern Territory people living in non-private dwellings were twice as likely to have an unknown Indigenous status than those living in private dwellings (16% compared with 8%).


INDIGENOUS STATUS UNKNOWN(a), by dwelling type


INDIGENOUS STATUS UNKNOWN DUE TO IMPUTATION OF PERSONS

6 Imputation is a statistical process used to predict characteristics when individuals do not return a form, or no response is provided to a question and a response cannot be derived. Although Census records are imputed when the ABS does not obtain a Census form for residents of both private and non-private dwellings, most imputation occurs for non-response from residents in private dwellings. Key demographic variables (sex, age, place of usual residence and registered marital status) are imputed if no Census form is received.

7 Indigenous status is coded to 'not stated' for imputed records. In 2011, almost three-quarters (73% or 768,600) of records with an unknown Indigenous status were imputed records. Unknown Indigenous status due to imputation was highest for the Northern Territory (85% or 14,700) and lowest for Tasmania (62% or 11,900).


INDIGENOUS STATUS UNKNOWN(a), Imputed records, 2011

Imputed records
Total unknown
no.
%
no.

New South Wales
248 084
72.3
342 923
Victoria
169 388
68.6
246 893
Queensland
168 735
75.3
224 206
South Australia
41 525
66.0
62 934
Western Australia
103 237
79.0
130 719
Tasmania
11 929
61.6
19 380
Northern Territory
14 695
84.5
17 391
Australian Capital Territory
10 883
77.7
14 005
Australia(b)
768 561
72.6
1 058 586


(a) Usual residence Census counts. Excludes overseas visitors.
(b) Includes
Other Territories.
Note: Totals and components may not be consistent within and between tables due to introduced random error to protect confidentiality of Census respondents - see Census Dictionary, 2011 (cat. no. 2901.0).


8 The proportion of imputed records nationally decreased slightly between the 2006 and 2011 Censuses (from 4.1% in 2006 to 3.6% in 2011). The Northern Territory had the highest rate of imputation in 2011 (7%), followed by Western Australia (5%), while Tasmania had the lowest (2%). Western Australia, Queensland, and the Northern Territory all recorded an increase in the number of imputed records over this period.


INDIGENOUS STATUS UNKNOWN(a)(b), Imputed records by proportion of state/territory(c)

2006
2011
Change
no.
%
no.
%
% points

New South Wales
280 805
4.3
248 084
3.6
-0.7
Victoria
179 743
3.6
169 388
3.2
-0.4
Queensland
165 161
4.2
168 735
3.9
-0.3
South Australia
44 538
2.9
41 525
2.6
-0.3
Western Australia
97 737
5.0
103 237
4.6
-0.4
Tasmania
13 523
2.8
11 929
2.4
-0.4
Northern Territory
14 059
7.3
14 695
6.9
-0.4
Australian Capital Territory
11 399
3.5
10 883
3.0
-0.5
Australia(d)
807 062
4.1
768 561
3.6
-0.5

(a) Usual residence Census counts. Excludes overseas visitors.
(b) Excludes records where there was no response to the Indigenous status question.
(c) Proportions are based on the total population for each state/territory.
(d) Includes Other Territories.
Note: Totals and components may not be consistent within and between tables due to introduced random error to protect confidentiality of Census respondents - see Census Dictionary, 2011 (cat. no. 2901.0).


INDIGENOUS STATUS UNKNOWN DUE TO ITEM NON-RESPONSE

Geographic distribution

9 In 2011, about one-quarter (290,000 or 27%) of records with an unknown Indigenous status were due to item non-response. Unknown Indigenous status due to item non-response was highest for Tasmania (38% or 7,400) and South Australia (34% or 21,400) and lowest for the Northern Territory (16% or 2,700).



INDIGENOUS STATUS UNKNOWN(a), Item non-response, 2011

Item non-response
Total unknown
no.
%
no.

New South Wales
94 837
27.7
342 923
Victoria
77 508
31.4
246 893
Queensland
55 468
24.7
224 206
South Australia
21 408
34.0
62 934
Western Australia
27 484
21.0
130 719
Tasmania
7 448
38.4
19 380
Northern Territory
2 696
15.5
17 391
Australian Capital Territory
3 120
22.3
14 005
Australia(b)
290 022
27.4
1 058 586


(a) Usual residence Census counts. Excludes overseas visitors.
(b) Includes
Other Territories.
Note: Totals and components may not be consistent within and between tables due to introduced random error to protect confidentiality of Census respondents - see Census Dictionary, 2011 (cat. no. 2901.0).


10 The national item non-response rate for the Indigenous status question decreased from 1.7% in 2006 to 1.4% in 2011. All states and territories saw a decline in the proportion of item non-response, with Tasmania recording the largest decline (from 2.0% of the population in 2006 to 1.5% in 2011), followed by New South Wales, Victoria, South Australia and Western Australia (each down 0.4 percentage points).


INDIGENOUS STATUS UNKNOWN(a)(b), Item non-response by proportion of state/territory(c)

2006
2011
Change
no.
%
no.
%
% points

New South Wales
110 469
1.8
94 837
1.4
-0.4
Victoria
86 285
1.8
77 508
1.4
-0.4
Queensland
59 748
1.6
55 468
1.3
-0.3
South Australia
24 780
1.7
21 408
1.3
-0.4
Western Australia
29 591
1.6
27 484
1.2
-0.4
Tasmania
9 380
2.0
7 448
1.5
-0.5
Northern Territory
2 446
1.4
2 696
1.3
-0.1
Australian Capital Territory
3 626
1.2
3 120
0.9
-0.3
Australia(d)
326 384
1.7
290 022
1.4
-0.4

(a) Usual residence Census counts. Excludes overseas visitors.
(b) Excludes imputed records.
(c) Proportions are based on total population for each state/territory.
(d) Includes
Other Territories.
Note: Totals and components may not be consistent within and between tables due to introduced random error to protect confidentiality of Census respondent - see Census Dictionary, 2011 (cat. no. 2901.0).


Age

11 In the 2011 Census, the rate of item non-response to the Indigenous status question was highest for people aged 75 years and over (4%), followed by those aged 65-74 years and those aged less than 15 years (both 2%).


INDIGENOUS STATUS UNKNOWN(a)(b), Item non-response by age, 2011

Aboriginal and Torres Strait Islander people
Non-
Indigenous people
Total population

Item non-response
Age group (years)
no.
no.
no.
no.
%

0-4
67 417
1 282 737
1 373 623
23 469
1.7
5-14
129 670
2 463 907
2 639 370
45 793
1.7
15-24
105 654
2 615 638
2 755 468
34 176
1.2
25-34
71 804
2 733 687
2 830 762
25 271
0.9
35-44
67 674
2 852 517
2 946 432
26 241
0.9
45-54
53 148
2 765 169
2 846 356
28 039
1.0
55-64
32 231
2 358 925
2 419 984
28 828
1.2
65-74
14 174
1 534 486
1 578 416
29 756
1.9
75 and over
6 598
1 293 698
1 348 748
48 452
3.6
Australia(c)
548 370
19 900 764
20 739 159
290 022
1.4

(a) Usual residence Census counts. Excludes overseas visitors.
(b) Excludes imputed records.
(c) Includes
Other Territories.
Note: Totals and components may not be consistent within and between tables due to introduced random error to protect confidentiality of Census respondents - see Census Dictionary, 2011 (cat. no. 2901.0).


Sex

12 Nationally, the rate of item non-response to the Indigenous status question was slightly higher for females (51%) than males (49%) in 2011. A similar trend was seen in most jurisdictions. In the Northern Territory, item non-response was greater for males than in any other jurisdiction (57% compared with 48% to 51% for all other states and the Australian Capital Territory). However, this is because there were considerably more males than females with Indigenous status unknown (due to item non-response) in the Northern Territory.


INDIGENOUS STATUS UNKNOWN(a)(b), Item non-response by sex, 2011

Males
Females
Total
no.
%
no.
%
no.

New South Wales
46 626
49.2
48 210
50.8
94 836
Victoria
38 194
49.3
39 310
50.7
77 504
Queensland
27 281
49.2
28 188
50.8
55 469
South Australia
10 279
48.0
11 130
52.0
21 409
Western Australia
13 714
49.9
13 771
50.1
27 485
Tasmania
3 682
49.4
3 766
50.6
7 448
Northern Territory
1 532
56.8
1 167
43.2
2 699
Australian Capital Territory
1 585
50.8
1 535
49.2
3 120
Australia(c)
142 918
49.3
147 104
50.7
290 022

(a) Usual residence Census counts. Excludes overseas visitors.
(b) Excludes imputed records.
(c) Includes
Other Territories.
Note: Totals and components may not be consistent within and between tables due to introduced random error to protect confidentiality of Census respondents - see Census Dictionary, 2011 (cat. no. 2901.0).


Census form type

13 An Interviewer Household Form is used in discrete Aboriginal and Torres Strait Islander communities. Very few people who were enumerated using the Interviewer Household Form had an unknown Indigenous status. Of the 83,900 people whose response in the 2011 Census was collected using the Interviewer Household Form, 0.5% (450 records) had an unknown Indigenous status. This was lower than in 2006 (0.7%).

Response to other Census questions

14 Responses to other Census questions may indicate that a record with a non-response for the Indigenous status question is likely to be for an Aboriginal and/or Torres Strait Islander person. In the 2011 Census there were 1,000 records with no response to the Indigenous status question, but with an Australian Aboriginal or Torres Strait Islander ancestry reported. The ABS does not edit these records to change Indigenous status during processing.

15 Of those people for whom a response to the Indigenous status question was not reported, 14% (40,700 records) did not have a response to any questions about birthplace, ancestry, language spoken at home or religious affiliation.

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