6248.0 - Wage and Salary Earners, Australia, Sep 2001  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 24/01/2002   
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RELIABILITY OF ESTIMATES

1 As the estimates in this publication are based on information relating to a sample of employers rather than a full enumeration, they are subject to sampling variability. That is, they may differ from the estimates that would have been produced if the information had been obtained from all employers. This difference, called sampling error, should not be confused with inaccuracy that may occur because of imperfections in reporting by respondents or in processing by the ABS. Such inaccuracy is referred to as non-sampling error and may occur in any enumeration whether it be a full count or a sample. Efforts have been made to reduce non-sampling error by careful design of questionnaires, detailed checking of returns and quality control of processing.

2 The sampling error associated with any estimate can be estimated from the sample results. One measure of sampling error is given by the standard error which indicates the degree to which an estimate may vary from the value that would have been obtained from a full enumeration (the ‘true’ figure). There are about two chances in three that a sample estimate differs from the true value by less than one standard error, and about nineteen chances in twenty that the difference will be less than two standard errors.

3 If the standard error of an estimate is large relative to the size of the estimate, the usefulness of that estimate is seriously impaired. For the tables in this publication, estimates with standard errors greater than 25% of the estimate have been labelled with an asterisk.

4 Standard errors of estimates of level, by industry and States and Territories, are shown in table A for the private sector and table B for the public sector and relate only to the middle month of the quarter. As the survey is conducted quarterly from a common sample of employer units, who report details of employees for each month of the quarter, standard errors on all estimates for employees in each month are of a similar magnitude.

5 Standard errors of estimates of movements provide a measure of the reliability of changes in the level of an estimate. Tables A and B show standard errors of movements in the level of estimates of employees for the private and public sectors respectively between the middle months of the most recent two quarters.

6 An example of the use of standard error on levels is as follows. If the estimated number of wage and salary earners was 5,800,000 with a standard error of 34,000, then there would be about two chances in three that a full enumeration would have given a figure in the range 5,766,000 to 5,834,000 and about nineteen chances in twenty that it would be in the range 5,732,000 to 5,868,000.

7 An example of the use of standard error on movements is as follows. If the estimated standard error for a quarterly change estimate of wage and salary earners was 15,000 and the quarterly change estimate between two quarters was 40,000 persons, then there would be about two chances in three that a full enumeration would have given a quarterly change estimate in the range 25,000 to 55,000 persons and about nineteen chances in twenty that it would been in the range 10,000 to 70,000 persons.

8 Quarterly movements in estimates of wage and salary earners are considered to be statistically significant where they exceed two standard errors.

9 Standard errors for earnings are approximately the same relative size as standard errors for the number of employees. Detailed standard errors are available on request.

Table A - STANDARD ERRORS - Wage and Salary Earners - Private Sector
New
Australian
South
South
Western
Northern
Capital
Wales
Victoria
Queensland
Australia
Australia
Tasmania
Territory
Territory
Australia
Industry
’000
’000
’000
’000
’000
’000
’000
’000
’000
LEVEL
Mining
1.0
0.2
0.6
0.1
2.3
0.2
0.1
-
2.6
Manufacturing
13.1
10.1
8.1
3.3
5.3
0.8
0.4
0.5
19.4
Electricity, gas and water supply
0.1
0.1
0.1
-
-
-
-
-
0.2
Construction
14.4
10.1
7.5
5.2
8.3
1.4
0.6
1.2
21.5
Wholesale trade
10.8
7.6
13.8
6.5
5.9
2.6
1.0
0.7
21.1
Retail trade
13.3
20.0
14.6
4.4
15.4
1.4
1.0
1.5
32.3
Accommodation, cafes and restaurants
10.6
9.7
7.4
4.8
3.9
1.0
1.7
1.0
17.3
Transport and storage
8.7
5.2
13.9
2.2
2.8
1.3
0.9
0.3
17.6
Communication services
3.4
0.9
0.3
0.3
0.6
-
-
-
3.5
Finance and insurance
4.6
6.0
4.2
2.6
2.2
0.6
0.1
0.5
9.2
Property and business services
20.8
49.2
20.8
8.2
17.2
1.8
2.8
5.6
60.7
Education
3.7
6.0
3.6
1.2
1.0
0.5
0.2
0.2
8.1
Health and community services
12.6
12.9
6.3
2.5
9.8
1.5
0.5
1.1
21.6
Cultural and recreational services
5.4
4.1
2.4
1.5
1.8
2.0
0.2
0.9
7.8
Personal and other services
6.6
7.9
2.1
1.7
3.5
1.4
0.9
1.0
11.3
All industries
39.6
59.3
35.9
14.7
28.5
5.1
3.9
6.4
86.3
QUARTERLY MOVEMENT
Mining
1.0
0.2
0.5
0.1
3.0
0.1
0.1
-
3.2
Manufacturing
6.1
5.1
3.8
2.3
2.5
0.8
0.2
0.3
9.5
Electricity, gas and water supply
0.1
-
0.1
0.1
-
-
-
-
0.1
Construction
8.5
4.8
4.2
3.9
5.5
0.4
0.4
0.5
12.6
Wholesale trade
4.8
6.6
6.4
4.7
1.9
1.0
0.6
0.3
11.5
Retail trade
8.5
18.0
11.3
3.7
4.0
2.7
0.9
1.3
23.6
Accommodation, cafes and restaurants
7.0
4.5
3.9
2.9
2.4
0.4
2.0
0.7
10.2
Transport and storage
5.4
3.5
9.5
2.0
1.0
1.0
1.0
0.3
11.7
Communication services
1.1
0.6
0.2
0.3
0.7
0.1
-
-
1.6
Finance and insurance
3.1
4.0
5.3
0.8
1.5
0.7
0.1
0.4
7.5
Property and business services
12.0
26.7
11.4
6.5
11.8
2.2
1.5
6.1
34.7
Education
2.8
1.5
2.1
0.2
1.4
0.7
0.1
0.1
4.1
Health and community services
6.9
5.7
4.3
2.9
5.9
2.2
0.6
0.9
12.1
Cultural and recreational services
3.3
1.5
1.0
2.0
1.6
2.0
0.2
0.3
5.0
Personal and other services
3.6
2.1
2.7
1.0
2.0
0.8
0.6
0.3
5.5
All industries
22.7
34.9
22.2
11.2
16.0
5.1
3.0
6.4
51.7
ANNUAL MOVEMENT
Mining
1.5
0.2
0.7
0.1
2.6
0.2
0.1
-
3.1
Manufacturing
11.5
14.2
7.9
2.7
6.9
0.9
0.4
0.5
21.2
Electricity, gas and water supply
0.1
0.1
0.1
-
-
-
-
-
0.2
Construction
20.7
12.8
7.9
6.7
8.8
1.2
0.7
1.4
27.9
Wholesale trade
10.0
9.1
8.8
5.4
1.1
2.5
1.1
0.7
17.2
Retail trade
15.8
17.1
17.4
5.5
9.1
5.1
1.6
1.7
31.2
Accommodation, cafes and restaurants
15.1
9.8
7.8
4.7
7.8
1.0
1.7
1.1
21.5
Transport and storage
8.1
4.6
6.9
2.8
3.0
1.3
1.8
0.3
12.4
Communication services
3.5
1.1
0.2
0.3
0.7
0.1
0.1
0.1
3.7
Finance and insurance
5.9
7.2
4.6
2.3
4.0
0.8
0.1
0.5
11.2
Property and business services
22.1
61.9
19.2
8.5
14.8
1.5
1.1
6.4
70.8
Education
5.9
4.5
3.4
1.4
1.8
0.6
0.2
0.4
8.5
Health and community services
14.7
9.7
9.0
4.0
9.4
2.3
0.7
1.4
22.4
Cultural and recreational services
10.7
4.9
6.0
2.5
1.8
2.0
0.3
1.0
13.7
Personal and other services
6.0
7.5
4.8
2.9
3.8
1.5
1.0
0.9
11.9
All industries
46.3
70.3
34.0
15.9
25.2
7.2
3.7
7.2
95.8

Table B - STANDARD ERRORS - Wage and Salary Earners - Public Sector
New South Wales
Victoria
Queensland
South Australia
Western Australia
Tasmania
Northern Territory
Australian Capital Territory
Australia
Industry
’000
’000
’000
’000
’000
’000
’000
’000
’000
LEVEL
Agriculture, forestry and fishing
0.5
-
-
-
-
-
-
-
0.5
Manufacturing
-
-
-
-
-
-
-
-
-
Electricity, gas and water supply
0.2
-
-
-
-
-
-
-
0.2
Construction
-
-
0.1
-
-
-
-
-
0.1
Transport and storage
-
-
0.1
-
-
-
-
-
0.1
Communication services
-
-
-
-
-
-
-
-
-
Finance and insurance
-
-
0.1
-
-
-
-
0.1
0.1
Property and business services
0.1
0.4
0.1
-
0.1
-
-
0.1
0.5
Government administration and defence
1.4
0.2
2.5
2.4
0.4
-
0.3
0.2
3.8
Education
0.2
3.3
0.1
-
-
-
-
0.1
3.3
Health and community services
0.1
0.4
0.8
0.1
0.1
-
-
-
0.9
Cultural and recreational services
0.1
0.3
0.1
0.2
-
-
0.1
-
0.4
Personal and other services
0.1
0.5
-
-
0.4
-
-
-
0.6
All industries(a)
1.5
3.4
2.7
2.4
0.6
0.1
0.3
0.2
5.2
QUARTERLY MOVEMENT
Agriculture, forestry and fishing
0.1
-
-
-
-
-
-
-
0.1
Manufacturing
-
-
-
-
-
-
-
-
-
Electricity, gas and water supply
0.1
0.1
-
-
-
-
-
-
0.1
Construction
-
-
-
-
-
-
-
-
-
Transport and storage
-
-
-
-
-
-
-
-
0.1
Communication services
-
-
-
-
-
-
-
-
-
Finance and insurance
-
-
-
-
-
-
-
0.1
0.1
Property and business services
0.1
0.3
-
0.1
0.1
-
-
-
0.4
Government administration and defence
1.2
0.3
1.9
2.3
1.5
-
0.2
0.3
3.5
Education
0.3
1.7
0.1
-
-
-
-
0.1
1.7
Health and community services
0.2
0.5
0.7
0.1
-
-
-
-
0.9
Cultural and recreational services
0.1
0.3
0.1
0.1
-
-
-
-
0.4
Personal and other services
0.1
0.4
-
-
-
-
-
-
0.4
All industries(a)
1.3
1.9
2.0
2.3
1.5
0.1
0.2
0.4
4.1
ANNUAL MOVEMENT
Agriculture, forestry and fishing
0.5
-
0.1
-
-
-
-
-
0.5
Manufacturing
-
-
-
-
-
-
-
-
-
Electricity, gas and water supply
0.2
-
0.1
-
-
-
-
-
0.2
Construction
-
-
0.1
-
-
-
-
-
0.1
Transport and storage
-
0.1
-
-
-
-
-
-
0.1
Communication services
-
-
-
-
-
-
-
-
-
Finance and insurance
0.1
-
0.1
0.1
-
-
-
0.1
0.2
Property and business services
0.1
0.6
0.1
0.1
0.1
-
0.2
0.1
0.6
Government administration and defence
1.5
0.4
3.0
2.4
0.4
-
0.3
0.4
4.2
Education
0.2
3.4
0.1
-
0.1
-
-
0.1
3.4
Health and community services
0.2
0.6
0.7
0.1
0.1
-
-
-
1.0
Cultural and recreational services
0.1
0.7
0.1
0.1
-
0.1
0.1
-
0.7
Personal and other services
0.1
0.2
0.2
-
0.4
-
-
-
0.5
All industries(a)
1.6
3.6
3.1
2.4
0.6
0.1
0.4
0.4
5.6
(a) Includes employees classified to Mining, Wholesale trade, Retail trade and Accommodation, cafes and restaurants.