8126.0 - Information and Communication Technology, Australia, 2002-03  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 07/09/2004   
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TECHNICAL NOTE DATA QUALITY


RELIABILITY OF THE ESTIMATES

1 When interpreting the results of a survey it is important to take into account factors that may affect the reliability of the estimates. Estimates provided in this publication are subject to non-sampling and sampling errors.



NON-SAMPLING ERRORS

2 Non-sampling errors may arise as a result of errors in the reporting, recording or processing of the data and can occur even if there is a complete enumeration of the population. These errors can be introduced through inadequacies in the questionnaire, treatment of non-response, inaccurate reporting by respondents, errors in the application of survey procedures, incorrect recording of answers and errors in data capture and processing.


3 The extent to which non-sampling error affects the results of the survey is difficult to measure. Every effort is made to minimise non-sampling error by careful design and testing of the questionnaire, efficient operating procedures and systems, and the use of appropriate methodology.


4 The 2002-03 ICT industries survey had a sample size of approximately 4,600 businesses. The final response rate was 95%; this included live operating businesses, businesses made out of scope, and businesses identified as no longer operating.



STANDARD ERRORS

5 The estimates presented in this publication are based on information obtained from a sample of businesses in the surveyed population. Consequently, the estimates are subject to sampling variability, that is, they may differ from the figures that would have been obtained if all units had been included in the survey. One measure of the likely difference is given by the standard error (SE), which indicates the extent to which an estimate might have varied by chance because only a sample was taken. There are about two chances in three that a sample estimate will differ by less than one SE from the figure that would have been obtained if a census had been conducted, and approximately 19 chances in 20 that the difference will be less than two SEs.


6 In this publication, sampling variability is measured by the relative standard error (RSE) which is obtained by expressing the SE as a percentage of the estimate to which it refers. The RSE is a useful measure in that it provides an immediate indication of the sampling error in percentage terms, and this avoids the need to refer also to the size of the estimate.


7 To illustrate, the estimated total income of all businesses classified to the ICT Manufacturing industry grouping is $4,392.3 million, the RSE is 1.7%, giving a standard error of $74.7 million (1.7% of $4,392.3 million). Therefore, there would be two chances in three that, if all units had been included in the survey, a figure in the range of $4,317.6 million to $4,467.0 million would have been obtained, and 19 chances in 20 (i.e. a confidence interval of 95%) that the figure would have been within the range of $4,242.9 million to $4,541.7 million. For more information about RSEs for estimates presented in this publication, please telephone the contact shown on the front page.


8 Most published estimates have RSEs less than 10%. Estimates that have a RSE between 10% and 25% are annotated with the symbol '^'. These estimates should be used with caution as they are subject to sampling variability too high for some purposes. Estimates with an RSE between 25% and 50% are annotated with the symbol '*', indicating that the estimates should be used with caution as they are subject to sampling variability too high for most practical purposes. Estimates with an RSE greater than 50% are annotated with the symbol '**' indicating that the sampling variability causes the estimates to be considered too unreliable for general use.


9 Estimates of RSEs for the key indicators in this publication are shown in the table below.

Relative standard errors for table 1.1 summary of operations
Businesses at end June
Employment at end June
ICT employees at end June
ICT income
Total income
%
%
%
%
%
ICT specialists
Manufacturing
Computer and business machines
17.3
6.8
6.1
4.3
4.2
Telecommunication, broadcasting and transceiving equipment
14.5
3.0
8.5
4.1
4.1
Electronic equipment n.e.c.
9.0
6.0
18.8
8.8
8.5
Electric cable and wire
18.4
5.9
2.9
2.5
2.3
Total manufacturing
8.0
2.6
6.2
2.8
2.8
Wholesale trade
Computers
7.5
3.1
5.2
3.4
3.4
Business machines
6.8
2.9
8.0
4.8
3.5
Electrical and electronic equipment n.e.c.
8.5
3.7
6.0
6.3
5.7
Total wholesale trade
4.9
2.1
3.8
2.9
2.7
Telecommunication services
5.5
1.3
3.1
1.9
1.8
Computer services
Data processing
20.9
18.6
26.6
13.3
12.9
Information storage and retrieval
19.0
7.4
10.4
4.4
4.4
Computer maintenance
9.1
5.0
6.0
4.8
4.6
Computer consultancy
2.9
3.0
3.5
2.3
2.3
Total computer services
2.8
2.8
3.3
2.2
2.2
Total
2.2
1.4
2.5
1.3
1.3
All businesses
Manufacturing
Computer and business machines
na
na
na
na
na
Telecommunication, broadcasting and transceiving equipment
na
na
na
na
na
Electronic equipment n.e.c.
na
na
na
na
na
Electric cable and wire
na
na
na
na
na
Total manufacturing
6.9
1.9
4.2
2.8
1.7
Wholesale trade
Computers
7.5
3.1
5.2
3.4
3.4
Business machines
4.6
2.8
6.9
4.5
3.9
Electrical and electronic equipment n.e.c.
3.6
2.4
5.4
6.1
3.3
Total wholesale trade
3.3
1.6
3.6
2.9
2.2
Telecommunication services
5.5
1.3
3.1
1.9
1.8
Computer services
Data processing
20.9
18.6
26.6
13.3
12.9
Information storage and retrieval
19.0
7.4
10.4
4.4
4.4
Computer maintenance
9.1
5.0
6.0
4.8
4.6
Computer consultancy
2.9
3.0
3.5
2.3
2.3
Total computer services
2.8
2.8
3.3
2.2
2.2
Total
2.1
1.2
2.4
1.3
1.1
na not available

Relative standard errors for table 1.1 summary of operations
Wages and salaries
Total expenses
Operating profit before tax
Capital expenditure
Industry value added
%
%
%
%
%
ICT specialists
Manufacturing
Computer and business machines
4.7
2.7
7.9
4.7
4.7
Telecommunication, broadcasting and transceiving equipment
2.1
3.8
np
4.9
3.4
Electronic equipment n.e.c.
6.7
8.1
22.6
9.6
6.8
Electric cable and wire
3.5
2.2
np
0.4
3.9
Total manufacturing
2.1
2.5
12.9
3.7
2.5
Wholesale trade
Computers
3.6
3.3
9.0
34.9
3.3
Business machines
2.4
3.6
9.0
7.2
2.2
Electrical and electronic equipment n.e.c.
2.5
5.6
15.2
11.1
4.0
Total wholesale trade
2.3
2.7
7.0
22.3
2.2
Telecommunication services
1.6
2.1
1.8
3.8
1.6
Computer services
Data processing
17.2
12.3
44.7
np
16.2
Information storage and retrieval
5.7
4.8
np
np
4.6
Computer maintenance
5.8
4.2
np
3.9
6.0
Computer consultancy
2.5
2.4
24.7
16.1
2.5
Total computer services
2.4
2.2
23.3
14.0
2.4
Total
1.2
1.4
2.8
3.7
1.1
All businesses
Manufacturing
Computer and business machines
na
na
na
na
na
Telecommunication, broadcasting and transceiving equipment
na
na
na
na
na
Electronic equipment n.e.c.
na
na
na
na
na
Electric cable and wire
na
na
na
na
na
Total manufacturing
1.4
1.5
7.6
2.8
1.6
Wholesale trade
Computers
3.6
3.3
9.0
34.9
3.3
Business machines
2.2
3.9
8.2
6.3
2.4
Electrical and electronic equipment n.e.c.
2.0
3.3
6.9
8.0
2.4
Total wholesale trade
1.8
2.1
5.1
18.7
1.8
Telecommunication services
1.6
2.1
1.8
3.8
1.6
Computer services
Data processing
17.2
12.3
44.7
np
16.2
Information storage and retrieval
5.7
4.8
np
np
4.6
Computer maintenance
5.8
4.2
np
3.9
6.0
Computer consultancy
2.5
2.4
24.7
16.1
2.5
Total computer services
2.4
2.2
23.3
14.0
2.4
Total
1.1
1.2
2.6
3.7
1.0
na not available
np not available for publication but included in totals where applicable, unless otherwise indicated