EXPLANATORY NOTES


INTRODUCTION

1 The statistics in this publication were compiled from data collected in the Energy Use and Conservation (EUC) Survey conducted throughout Australia in March 2014 as a supplement to the Australian Bureau of Statistics' (ABS) monthly Labour Force Survey (LFS). The aim of the Survey was to collect information on how households use and conserve energy. This survey is a continuation of a series of surveys on this topic that has been conducted every three years since March 1994. The previous EUC Survey was conducted in March 2011. It is intended that EUC 2014 will be the last iteration of the survey.

2 The publication Labour Force, Australia (cat. no. 6202.0) contains information about the LFS survey design, scope, coverage and population benchmarks. This information also applies to supplementary surveys. The LFS publication contains definitions of demographic characteristics and information about telephone interviewing.


SCOPE AND COVERAGE

3 The scope of the EUC Survey was households in urban, rural, remote and very remote areas in all states and territories of Australia, excluding households in Indigenous Community Strata.

4 The EUC Survey scope excluded households in special dwellings (such as hotels, university residences, boarding schools, hospitals, nursing homes and prisons).

5 The coverage of the survey was the same as the scope.


DATA COLLECTION

6 After taking into account sample loss, the response rate for the survey was 86%. In total, information was collected from 10,809 fully responding households.

7 Information was collected from any responsible adult in the household aged 18 years and over, who was asked to respond on behalf of the household.

8 Data was collected using Computer Assisted Interviewing whereby responses were recorded directly onto an electronic questionnaire in a notebook computer, usually during a telephone interview.


WEIGHTING, BENCHMARKS AND ESTIMATION

Weighting

9 Weighting is the process of adjusting results from a sample survey to infer results for the total population. To do this, a 'weight' is allocated to each enumerated household. The weight is a value which indicates how many households in the population are represented by the sample household.

10 The first step in calculating weights for each unit is to assign an initial weight, which is the inverse of the probability of the unit being selected in the survey. For example, if the probability of a household being selected in the survey was 1 in 700, then the household would have an initial weight of 700 (that is, it represents 700 households).

Benchmarks

11 The initial weights are then calibrated to align with independent estimates of the population, referred to as benchmarks. The population included in the benchmarks is the survey scope. This calibration process ensures that the weighted data conform to the independently estimated distribution of the population described by the benchmarks rather than to the distribution within the sample itself. Calibration to population benchmarks helps to compensate for over or under-enumeration of particular categories of households which may occur due to either the random nature of sampling or non-response.

12 The survey uses Estimated Resident Population based household benchmarks for the capital city and balance of state/territory for each state and territory of Australia, as at 31 March 2014.

Estimation

13 Survey estimates of household counts are obtained by summing the weights of households with the characteristic of interest.


RELIABILITY OF ESTIMATES

14 All sample surveys are subject to error which can be broadly categorised as either:

• sampling error
• non-sampling error.

15 Sampling error is the difference between the published estimate, derived from a sample of dwellings, and the value that would have been produced if all dwellings in scope of the survey had been included. For more information refer to Data Quality (Technical Note).

16 Non-sampling error may occur in any collection, whether it is based on a sample or a full count of the population such as a census. Sources of non-sampling error include: non-response; errors in reporting by respondents or recording of answers by interviewers; and errors in coding and processing data. Every effort was made to reduce the non-sampling error by: careful design and testing of the questionnaire; training and supervision of interviewers; follow-up of respondents; and extensive editing and quality control procedures at all stages of data processing.


CONFIDENTIALITY

17 In accordance with the Census and Statistics Act, 1905, all published estimates are subjected to a confidentiality process before release. This process is undertaken to minimise the risk of identifying particular individuals, families, households or dwellings in aggregate statistics, through analysis of published data.

18 To minimise the risk of identifying individuals in aggregate statistics, a technique is used to randomly adjust cell values. This technique is called perturbation. Perturbation involves small random adjustment of the statistics and is considered the most satisfactory technique for avoiding the release of identifiable statistics while maximising the range of information that can be released. These adjustments have a negligible impact on the underlying pattern of the statistics.

19 After perturbation, a given published cell value will be consistent across all tables. However, adding up cell values to derive a total will not necessarily give the same result as published totals.

20 Where a footnote is not included on an estimated total, it should be assumed that any discrepancy between the total and the sum of its components is due to the effects of rounding or perturbation.


DATA QUALITY

21 Information recorded in this survey is as reported by respondents and hence may differ from that which might be obtained from other sources or via other methodologies. This factor should be considered when interpreting the estimates in this publication.


DATA COMPARABILITY

Comparability of Time Series

22 The previous EUC survey was conducted in March 2011. Links to the 2011 and 2008 surveys are available on the Past & Future Releases tab. Prior to 2008, the annual publication Environmental Issues: People's Views and Practices (cat. no. 4602.0) focussed on one of three rotating topics each year: Water Use and Conservation, Energy Use and Conservation, and Waste Management, Transport and Motor Vehicle Usage.

23 The ABS seeks to maximise consistency and comparability over time by minimising changes to surveys. Sound survey practice, however, requires ongoing development to maintain and improve the integrity of the data. When comparing data from different cycles of the survey, users are advised to consult the questionnaires (available from the Downloads tab), check whether question wording or sequencing has changed, and consider whether this may have had an impact on the way questions were answered by respondents.

24 The ABS recommends that due to changes in data collection methodology, the following data items are not comparable with equivalent items in the 2011 cycle of the EUC Survey:

• All geographic items except State, due to the introduction of the ASGS
• Tenure type
• All sources of energy used by the household
• Whether household has solar hot water or solar electricity
• All sources of energy for main hot water system
• All sources of energy for all hot water systems
• Type of hot water system
• All items to do with televisions, laptops, desktop computers, printers/scanners/faxes, digital boxes, DVD or Blu-ray players, stereo systems and surround sound systems

25 For some data items there was a change in the way that data was collected between 2011 and 2014 which may affect comparability of data over time. The ABS recommends that users exercise caution when comparing these data items with equivalent items in the 2011 cycle of the EUC Survey:

• Material of outside walls
• Type of floor construction
• Main reason insulation installed
• Where insulation is installed
• Main type of insulation in roof or ceiling
• Main type of insulation in walls
• Type of booster for solar hot water system (main)
• Main energy source for cooktop
• Main energy source for oven
• Main source of energy for heating
• Main type of heating used
• Whether main heater is reverse cycle
• Whether main air conditioner is reverse cycle
• Main system of air conditioner used
• Main type of air conditioner used
• All items to do with game consoles

26 The following data items were collected in 2011 but not in 2014:

• All sources of energy for inside household
• All sources of energy for outside household
• Wood purchased or free
• Source of wood
• Sources of fuel for secondary hot-water system
• Awareness of Green Power
• Secondary source of heating
• Whether secondary heating reverse cycle
• Use reverse cycle air conditioner for heating
• Number of computers/printers ever left on standby

27 The following data items were collected in 2014 but not in 2011:

• Whether household was responsible for installation of insulation
• Type of internal window covering
• Type of external window covering
• Whether household uses smart phone
• How many smart phones household uses
• Whether household uses tablet
• How many tablets household uses

Comparability with other ABS surveys

28 Caution should be taken in comparisons across ABS surveys and with administrative by-product data that addresses energy use. Estimates from the EUC survey may differ from those obtained from other surveys (such as the Household Energy Consumption Survey) due to differences in survey mode, methodology and questionnaire design.


CLASSIFICATIONS

29 Geographic areas are classified according to the Australian Statistical Geography Standard (ASGS). The EUC 2014 survey is the first survey in this series to use this ASGS structure and as a result comparison between the 2014 and 2011 (and previous) data for 'capital city' and 'balance of state' should be undertaken with caution as the areas are not necessarily comparable across years.


PRODUCTS AND SERVICES

Data Cubes

30 A Data Cube containing all tables in Excel spreadsheet format can be found on the Downloads tab. The spreadsheet presents tables of estimates and proportions, and their corresponding relative standard errors (RSEs).

Customised data requests

31 Special tabulations of the data are available on request. Subject to confidentiality and sampling variability constraints, tabulations can be produced from the survey incorporating data items, populations and geographic areas, tailored to individual requirements. These are provided in electronic form. A list of data items from the 2014 EUC Survey is available from the Downloads tab. All inquiries should be made to the National Information and Referral Service on 1300 135 070, or email client.services@abs.gov.au.

Inquiries

32 For further information about these and related statistics, contact the National Information and Referral Service on 1300 135 070, or email client.services@abs.gov.au. The ABS Privacy Policy outlines how the ABS will handle any personal information that you provide to us.


ACKNOWLEDGEMENTS

33 ABS surveys draw extensively on information provided by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated and without it, the wide range of statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.


NEXT SURVEY

34 The ABS does not plan to conduct this survey in the future.