Latest release

# National Health Survey: Health Literacy methodology

Reference period
2018
Released
15/05/2020
Next release Unknown
First release

## Explanatory notes

### Introduction

1 This publication presents key indicators from the 2018 Health Literacy Survey (HLS), including information on:

• nine domains of health literacy (such as how people find, understand and use health information, how they manage their health and interact with healthcare providers) together with:
• key health risk factors and health conditions, and
• demographic, socioeconomic characteristics.

2 The HLS was conducted throughout Australia from January 2018 to August 2018.

### Scope of the survey

3 The HLS was conducted with a sample drawn from respondents 18 years and over who had already participated in the 2017-18 National Health Survey (NHS) and agreed to be contacted for further ABS surveys. As such the HLS data was combined with that of the NHS, and information related to survey scope, coverage, data collection, input coding and data quality issues for both the NHS and HLS are included below where relevant.

4 Urban and rural areas in all states and territories were included, while Very Remote areas of Australia and discrete Aboriginal and Torres Strait Islander communities were excluded. These exclusions are unlikely to affect national estimates, and will only have a minor effect on aggregate estimates produced for individual states and territories, excepting the Northern Territory where the population living in Very Remote areas accounts for around 20.3% of persons.

5 Non-private dwellings such as hotels, motels, hospitals, nursing homes and short-stay caravan parks were excluded from the survey. This may affect estimates of the number of people with some long-term health conditions (for example, conditions which may require periods of hospitalisation or long term care).

6 The HLS was limited to adults aged 18 years and over.

7 The following groups were excluded from the survey:

• certain diplomatic personnel of overseas governments, customarily excluded from the Census and estimated resident population;
• persons whose usual place of residence was outside Australia;
• members of non-Australian Defence forces (and their dependents) stationed in Australia; and
• visitors to private dwellings.

### Sample design

8 Dwellings for the NHS were selected at random using a multistage area sample of private dwellings. The initial sample selected for the survey consisted of approximately 25,109 dwellings. This was reduced to a sample of 21,544 after sample loss (for example, households selected in the survey which had no residents in scope of the survey, vacant or derelict buildings, buildings under construction). Of those remaining dwellings, 16,376 (or 76.0%) were fully or adequately responding, yielding a total sample for the survey of 21,315 persons.

NSWVic.QldSAWATas.NTACTAust.
NHS 17-18 Households in sample3 2712 6123 3641 6581 6561 6051 0891 12116 376
Households approached for HLS that agreed to be contacted (after sample loss)1 3031 1501 3348247657164346987224
Fully responding HLS sample1 0219241 0476506015923486085790
Response rate for HLS only (%)78.480.378.578.972.982.780.287.180.1
Response rate of total NHS sample (%)31.235.331.139.236.336.931.954.235.3

### Approached sample, final sample and response rates

9 The sample for the HLS was taken from the total initial sample of 16,376 fully or adequately responding households enumerated for the NHS. The actual HLS sample approached was 7,224 households. Of these households in the actual sample, 5,790 (80.1%) were fully responding households. This represents an overall response rate of 35.3% when measured against the total initial sample of respondents to the NHS.

### Data collection

11 The HLS was conducted by trained ABS interviewers over the telephone using Computer Assisted Telephone Interviewing (CATI). Information gathered through the 2017-18 NHS was collected via personal interviews with selected residents in sampled dwellings. One adult (aged 18 years and over) in each dwelling was selected and interviewed about their own health characteristics as well as information about the household (for example, income of other household members).

### Weighting, benchmarking and estimation

12 Weighting is a process of adjusting results from a sample survey to infer results for the in-scope total population. To do this, a weight is allocated to each sample unit; for example, a household or a person. The weight is a value which indicates how many population units are represented by the sample unit. The file contains weights for both the 2017-18 NHS and the HLS. When analysing information from the HLS, the HLS weights must be used.

13 The first step in calculating NHS weights for each person was to assign an initial weight, which was equal to the inverse of the probability of being selected in the survey. For example, if the probability of a person being selected in the survey was 1 in 600, then the person would have an initial weight of 600 (that is, they represent 600 others). An adjustment was then made to these initial weights to account for the time period in which a person was assigned to be enumerated.

14 The weights are calibrated to align with independent estimates of the population of interest, referred to as 'benchmarks', in designated categories of sex by age by area of usual residence. Weights calibrated against population benchmarks in this way compensate for over or under-enumeration of particular categories of persons and ensure that the survey estimates conform to the independently estimated distribution of the population by age, sex and area of usual residence, rather than to the distribution within the sample itself.

15 The NHS was benchmarked to the estimated resident population living in private dwellings in non-Very Remote areas of Australia at 31 December 2017. Excluded from these benchmarks were persons living in discrete Aboriginal and Torres Strait Islander communities. The benchmarks, and hence the estimates from the survey, do not (and are not intended to) match estimates of the total Australian resident population (which include persons living in Very Remote areas or in non-private dwellings, such as hotels) obtained from other sources.

16 HLS data was re-weighted at the person-level for the population aged 18 years and over. The HLS weights were calibrated to the NHS person-level weights for some key variables (i.e. collapsed highest level of education; one-digit country of birth; current daily smoker status; self-assessed health; collapsed disability status; heart/stroke/vascular disease status; and overweight/obese status).

17 Survey estimates of counts of persons are obtained by summing the weights of persons with the characteristic of interest. Estimates of non-person counts (for example, number of health conditions) are obtained by multiplying the characteristic of interest with the weight of the reporting person and aggregating.

18 In addition to weighted estimates. this release also includes weighted mean Health Literacy Scores. This summary statistic is expressed as the mean of the values for each health literacy domain, falling within a range of 1-4 or 1-5 depending on the domain.

### Reliability of estimates

19 All sample surveys are subject to sampling and non-sampling error.

20 Sampling error is the difference between estimates, derived from a sample of persons, and the value that would have been produced if all persons in scope of the survey had been included. Indications of the level of sampling error for estimates are given by the Relative Standard Error (RSE) and 95% Margin of Error (MoE). For more information refer to the Technical Note - Reliability of Estimates.

21 In this publication, estimates with an RSE of 25% to 50% are preceded by an asterisk (e.g. *3.4) to indicate that the estimate has a high level of sampling error relative to the size of the estimate, and should be used with caution. Estimates with an RSE over 50% are indicated by a double asterisk (e.g. **0.6) and are generally considered too unreliable for most purposes.

22 Margins of Error are provided for proportions to assist users in assessing the reliability of these data. Estimates of proportions with an MoE more than 10% are annotated to indicate they are subject to high sample variability and particular consideration should be given to the MoE when using these estimates. Depending on how the estimate is to be used, an MoE greater than 10% may be considered too large to inform decisions. In addition, estimates with a corresponding standard 95% confidence interval that includes 0% or 100% are annotated with a # to indicate that they are usually considered unreliable for most purposes.

23 Non-sampling error may occur in any data collection, whether it is based on a sample or a full count such as a census. Non-sampling errors occur when survey processes work less effectively than intended. Sources of non-sampling error include non-response, errors in reporting by respondents or in recording of answers by interviewers, and errors in coding and processing data.

23 Non-response occurs when people are unable to or do not cooperate, or cannot be contacted. Non-response can affect the reliability of results and can introduce a bias. The magnitude of any bias depends on the rate of non-response and the extent of the difference between the characteristics of those people who responded to the survey and those who did not.

24 The following methods were adopted to reduce the level and impact of non-response for the 2017-18 NHS:

• face-to-face interviews with respondents;
• the use of proxy interviews in cases where language difficulties were encountered, noting the interpreter was typically a family member;
• follow-up of respondents if there was initially no response; and
• weighting to population benchmarks to reduce non-response bias.

25 To reduce the level and impact of non-response for the HLS, respondents were followed-up via telephone on multiple occasions if there was initially no response.

### Interpretation of results

26 Care has been taken to ensure that results are as accurate as possible. This includes thorough design and testing of the questionnaire, interviews being conducted by trained ABS interviewers, and quality control procedures throughout data collection, processing and output. There remain, however, other factors which may have affected the reliability of results, and for which no specific adjustments can be made. The following factors should be considered when interpreting these estimates:

• Information recorded in the survey is essentially 'as reported' by respondents, and hence may differ from information available from other sources or collected using different methodology; for example, information about health conditions is self-reported and, while not directly based on a diagnosis by a medical practitioner in the survey, respondents were asked whether they had ever been told by a doctor or nurse that they had a particular health condition. Conditions which have a greater effect on people's well-being or lifestyle, or those specifically mentioned in survey questions, are expected in general to have been better reported than others; and
• Some respondents may have provided responses that they felt were expected, rather than those that accurately reflected their own situation. Every effort has been made to minimise such bias through the development and use of appropriate survey methodology;

27 For reporting purposes, the HLS response category of 'difficult' combines three separate response variables contained in the HLQ: ‘sometimes difficult’, ‘usually difficult’ and ‘cannot do or always difficult’. This applies to domains 6 to 9 only. For domains 1 to 5, the 'strongly disagree' and 'disagree' categories from the HLQ have been combined and are referred to as 'strongly disagree/disagree'.

### Classifications

28 In the HLS, respondents were told that the term 'healthcare providers' encompassed doctors, nurses, physiotherapists, dieticians and any other health workers that respondents seek advice or treatment from.

29 Long-term health conditions reported by respondents in the NHS are presented using a classification originally developed for the 2001 NHS by the Family Medicine Research Centre, University of Sydney, in conjunction with the ABS. The classification is based on the 10th revision of the International Classification of Diseases (ICD) and is used for all years from 2001 to 2017-18.

30 Country of birth is classified to the Standard Australian Classification of Countries (cat. no. 1269.0).

31 Main language spoken at home is classified according to the Australian Standard Classification of Languages (cat. no. 1267.0).

32 Descriptions of data items such as Body Mass Index and the Kessler Psychological Distress Scale (K10) are included in the Glossary to this publication.

### Confidentiality

33 The Census and Statistics Act, 1905 provides the authority for the ABS to collect statistical information, and requires that statistical output shall not be published or disseminated in a manner that is likely to enable the identification of a particular person or organisation. This requirement means that the ABS must take care and make assurances that any statistical information about individual respondents cannot be derived from published data.

34 To minimise the risk of identifying individuals in aggregate statistics, a technique known as perturbation is used to randomly adjust cell values. Perturbation involves a 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. 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.

35 Perturbation has been applied to the estimates in this release. Perturbation has not been applied to the mean Health Literacy Scores.

### Rounding

36 Estimates presented in this publication have been rounded.

37 Proportions presented in this publication are based on unrounded estimates. Calculations using rounded estimates may differ from those published.

### Acknowledgements

38 ABS publications draw extensively on information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated; 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.

### Products and services

39 Summary results from the HLS are available in spreadsheet form from the 'Data oownloads' section in this release. The statistics presented are only a selection of the information collected.

40 For users who wish to undertake more detailed analysis, a TableBuilder product for the 2017-18 NHS, which includes HLS data, will be available on 30 April 2019. TableBuilder is an online tool for creating tables from ABS survey data, where variables can be selected for cross-tabulation. It has been developed to complement the existing suite of ABS microdata products and services including Census TableBuilder and CURFs. Further information about ABS microdata, including conditions of use, is available via the Microdata section on the ABS website.

41 Customised tabulations 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 selected to meet individual requirements.

### Related publications

42 Current publications and other products released by the ABS are listed on the ABS website. The ABS also issues a daily Release Advice on the website which details products to be released in the week ahead.

## Technical note - reliability of estimates

1 Two types of error are possible in an estimate based on a sample survey: sampling error and non-sampling error. The sampling error is a measure of the variability that occurs by chance because a sample, rather than the entire population, is surveyed. Since the estimates in this publication are based on information obtained from occupants of a sample of dwellings they are subject to sampling variability; that is, they may differ from the figures that would have been produced if all dwellings had been included in the survey. One measure of the likely difference is given by the standard error (SE). 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 all dwellings had been included, and about 19 chances in 20 that the difference will be less than two SEs.

2 Another measure of the likely difference is the relative standard error (RSE), which is obtained by expressing the RSE as a percentage of the estimate. The RSE is a useful measure in that it provides an immediate indication of the percentage errors likely to have occurred due to sampling, and thus avoids the need to refer also to the size of the estimate.

$$R S E \%=\left(\frac{S E}{E s t i m a t e}\right) \times 100$$

3 RSEs for published estimates are supplied in Excel data tables, available via the Data downloads section.

4 The smaller the estimate the higher is the RSE. Very small estimates are subject to such high SEs (relative to the size of the estimate) as to detract seriously from their value for most reasonable uses. In the tables in this publication, only estimates with RSEs less than 25% are considered sufficiently reliable for most purposes. However, estimates with larger RSEs, between 25% and less than 50% have been included and are preceded by an asterisk (eg *3.4) to indicate they are subject to high SEs and should be used with caution. Estimates with RSEs of 50% or more are preceded with a double asterisk (eg**0.6). Such estimates are considered unreliable for most purposes.

5 The imprecision due to sampling variability, which is measured by the SE, should not be confused with inaccuracies that may occur because of imperfections in reporting by interviewers and respondents and errors made in coding and processing of data. Inaccuracies of this kind are referred to as the non-sampling error, and they may occur in any enumeration, whether it be in a full count or only a sample. In practice, the potential for non-sampling error adds to the uncertainty of the estimates caused by sampling variability. However, it is not possible to quantify the non-sampling error.

### Standard errors of proportions and percentages

6 Proportions and percentages formed from the ratio of two estimates are also subject to sampling errors. The size of the error depends on the accuracy of both the numerator and the denominator. For proportions where the denominator is an estimate of the number of persons in a group and the numerator is the number of persons in a sub-group of the denominator group, the formula to approximate the RSE is given below. The formula is only valid when x is a subset of y.

$$\operatorname{RSE}\left(\frac{x}{y}\right)=\sqrt{\operatorname{RSE}(x)^{2-} \operatorname{RSE}(y)^{2}}$$

### Comparison of estimates

7 Published estimates may also be used to calculate the difference between two survey estimates. Such an estimate is subject to sampling error. The sampling error of the difference between two estimates depends on their SEs and the relationship (correlation) between them. An approximate SE of the difference between two estimates (x-y) may be calculated by the following formula:

$$S E(x-y)=\sqrt{[S E(x)]^{2}+[S E(y)]^{2}}$$

8 While the above formula will be exact only for differences between separate and uncorrelated (unrelated) characteristics of sub-populations, it is expected that it will provide a reasonable approximation for all differences likely to be of interest in this publication.

9 Another measure is the Margin of Error (MOE), which describes the distance from the population value that the sample estimate is likely to be within, and is specified at a given level of confidence. Confidence levels typically used are 90%, 95% and 99%. For example, at the 95% confidence level the MOE indicates that there are about 19 chances in 20 that the estimate will differ by less than the specified MOE from the population value (the figure obtained if all dwellings had been enumerated). The 95% MOE is calculated as 1.96 multiplied by the SE.

10 The 95% MOE can also be calculated from the RSE by:

$$\large\operatorname{MOE}(y) \approx \frac{R S E(y) \times y}{100} \times 1.96$$

11 The MOEs in this publication are calculated at the 95% confidence level. This can easily be converted to a 90% confidence level by multiplying the MOE by:

$$\LARGE\frac{1.645}{1.96}$$

or to a 99% confidence level by multiplying by a factor of:

$$\LARGE\frac{2.576}{1.96}$$

12 A confidence interval expresses the sampling error as a range in which the population value is expected to lie at a given level of confidence. The confidence interval can easily be constructed from the MOE of the same level of confidence by taking the estimate plus or minus the MOE of the estimate.

### Significance testing

13 For comparing estimates between surveys or between populations within a survey it is useful to determine whether apparent differences are 'real' differences between the corresponding population characteristics or simply the product of differences between the survey samples. One way to examine this is to determine whether the difference between the estimates is statistically significant. This is done by calculating the standard error of the difference between two estimates (x and y) and using that to calculate the test statistic using the formula below:

$$\large\frac{|x-y|}{S E(x-y)}$$

where

$$\large S E(y) \approx \frac{R S E(y) \times y}{100}$$

14 If the value of the statistic is greater than 1.96 then we may say there is good evidence of a statistically significant difference at 95% confidence levels between the two populations with respect to that characteristic. Otherwise, it cannot be stated with confidence that there is a real difference between the populations.

## Glossary

### Show all

Definitions used in the National Health Survey (NHS) and Health Literacy Survey (HLS) are not necessarily identical to those used for similar items in other collections.

#### Adequate consumption of fruit and vegetables

A balanced diet, including sufficient fruit and vegetables, reduces a person's risk of developing conditions such as heart disease and diabetes. The National Health and Medical Research Council's (NHMRC) 2013 Australian Dietary Guidelines recommend a minimum number of serves of fruit and vegetables each day, depending on a person's age and sex, to ensure good nutrition and health. Adequacy of intake (consumption) is based on whether a respondent's reported usual daily intake in serves of fruit or vegetables meets or exceeds each recommendation. More information about the guidelines can be found under Usual daily intake of fruit and Usual daily intake of vegetables in this glossary.

#### Adult literacy and life skills survey (ALLS)

The adult literacy and life skills survey (ALLS) was conducted in Australia in 2006 as part of an international study coordinated by Statistics Canada and the Organisation for Economic Co-operation and Development (OECD). The ALLS is designed to identify and measure literacy, numeracy and problem-solving skills. An additional literacy measure, health literacy, was also available.

#### Alcohol consumption risk level

Alcohol consumption risk levels in the National Health Survey: First Results, 2017-18 (cat. no. 4364.0.55.001) have been assessed using the 2009 National Health and Medical Research Council (NHMRC) guidelines for the consumption of alcohol.

The 2009 lifetime risk guideline (guideline 1) was assessed using average daily consumption of alcohol for persons aged 15 years and over, derived from the type, brand, number and serving sizes of beverages consumed on the three most recent days of the week prior to interview, in conjunction with the total number of days alcohol was consumed in the week prior to interview.

The 2009 single occasion risk guideline (guideline 2) was assessed using questions on the number of times in the last 12 months a person's consumption exceeded specified levels.

The NHMRC drinking guidelines provide two universal guidelines for adults, one for children and young people and one for pregnant and breast feeding women. The following table outlines the risk level for each group. The NHMRC drinking guidelines advise that for anyone under the age of 18, not consuming alcohol is the safest option. However this population group has been assessed in the NHS against the universal guidelines for adults, that is guideline 1 and 2. This allows an assessment of the levels of risky drinking for this age group for both single occasion and lifetime risk.

Level of risk
Does not exceed guidelineExceeds guideline
Guideline 1 - Lifetime riskup to and including 2 standard drinksmore than 2 standard drinks
Guideline 2 - Single occasion riskup to and including 4 standard drinksmore than 4 standard drinks (c)
Guideline 3 - Children and young peopleNo drinking is the safest optionAlcohol consumed
Guideline 4 - Pregnant and breast feeding womenNo drinking is the safest optionAlcohol consumed

a. One standard drink contains 12.5 mLs of alcohol.
b. Guidelines relate to both males and females.
c. On at least one occasion in the last 12 months.

#### 2009 NHMRC guidelines(a)(b)

Alcohol consumption status information was also collected for persons who did not consume any alcohol in the 7 days prior to interview, categorised as:

• Last consumed more than one week to less than 12 months ago;
• Last consumed 12 months or more ago; and
• Never consumed.

For more detailed information on the 2009 NHMRC guidelines, see the Australian Guidelines to Reduce Health Risks from Drinking Alcohol

For a detailed explanation of the method used to measure alcohol consumption in ABS health surveys, see Alcohol Consumption in Australia: A Snapshot (cat. no. 4832.0.55.001).

#### Arthritis

Arthritis is characterised by an inflammation of the joints often resulting in pain, stiffness, disability and deformity.

#### Asthma

A chronic disease marked by episodes of wheezing, chest tightness and shortness of breath associated with widespread narrowing of the airways within the lungs and obstruction of airflow. To be current, symptoms of asthma or treatment for asthma must have occurred in the last 12 months.

#### Accessibility/remoteness index of Australia

Accessibility/Remoteness Index of Australia (ARIA) was developed by the Commonwealth Department of Health and Aging (DoHA) and the National Key Centre for Social Applications of Geographic Information Systems (GISCA). ARIA measures the remoteness of a point based on the physical road distance to the nearest Urban Centre in each of five size classes. For more information on how ARIA is defined see Information Paper: ABS Views on Remoteness (cat. no. 1244.0) and Information Paper: Outcomes of ABS Views on Remoteness Consultation, Australia (cat. no. 1244.0.00.001). Also refer to Census Geography Paper 03/01 - ASGC Remoteness Classification - Purpose and Use, available from the ABS website.

#### ASGC and ASGS remoteness structure

The Remoteness Structure for the Australian Standard Geographical Classification (ASGC) 2006 and the Australian Statistical Geography Standard (ASGS) 2016, has 5 categories based on an aggregation of geographical areas which share common characteristics of remoteness, determined in the context of Australia as a whole. The criteria for these categories are based on the Accessibility/Remoteness Index of Australia (ARIA). For more details, see Accessibility/Remoteness Index of Australia definition above and the ASGC page on the ABS website.

#### Australia's physical activity and sedentary behaviour guidelines

The 2014 Guidelines recommend that:

• Adults (18-64 years) should be active most days of the week, accumulate 150 to 300 minutes moderate intensity physical activity or 75 to 150 minutes of vigorous intensity physical activity (or an equivalent combination each week), and do muscle strengthening activities on at least two days each week.
• Older Australians (65 years and over) should accumulate at least 30 minutes of moderate intensity physical activity on most, preferably all, days.

#### Blood pressure

See High blood pressure, Diastolic blood pressure and Systolic blood pressure.

#### Bodily pain

Indication of the severity of any bodily pain that the respondent had experienced (from any and all causes) during the last 4 weeks. This is a self-assessment from the SF36 international instrument.

#### Body mass index

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, overweight and obesity. It is calculated from height and weight information, using the formula weight (kg) divided by the square of height (m). In the 2017-18 NHS, respondents were also asked to self report their height and weight. To produce a measure of the prevalence of underweight, normal weight, overweight or obesity in adults, BMI values are grouped according to the table below.

CategoryRange
UnderweightLess than 18.50
Normal range18.50 —24.99
Overweight25.00 — 29.99
Obese I30.00 — 34.99
Obesity class II35.00 — 39.99
Obesity class III40.00 or more

#### Cancer (malignant neoplasms)

Cancer is a condition in which the body's cells grow and spread in an uncontrolled manner. A cancerous cell can arise from almost any cell, and therefore cancer can be found almost anywhere in the body.

#### Chronic conditions

These consist of:

• Arthritis;
• Asthma;
• Back problems (dorsopathies);
• Cancer (malignant neoplasms);
• Chronic obstructive pulmonary disease (COPD);
• Diabetes mellitus;
• Heart, stroke and vascular disease;
• Kidney disease;
• Mental and behavioural conditions; and
• Osteoporosis,

and are selected for reporting because they are mostly common, pose significant health problems, have been the focus of recent population health surveillance efforts, and action can be taken to prevent their occurrence.

In this publication, persons were included in estimates when they reported that their condition was current and long-term; that is, their condition was current at the time of interview and had lasted, or was expected to last, 6 months or more. In the NHS 2014-15 and 2017-18, estimates also included persons who reported they had diabetes mellitus, angina, heart attack, other ischaemic heart diseases, stroke or other cerebrovascular diseases, but that these conditions were not current and long-term at the time of interview.

#### Chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is a collective term for a group of conditions that include emphysema, chronic bronchitis and chronic asthma that is not fully reversible. Emphysema and chronic bronchitis are the two most common forms of COPD.

#### Conditions

Health conditions reported by respondents in the NHS are presented using a classification originally developed for the 2001 NHS by the Family Medicine Research Centre, University of Sydney, in conjunction with the ABS. The classification is based on the 10th revision of the International Classification of Diseases (ICD) and is used for all years from 2001 to 2017-18. See also Long-term health condition.

#### Current daily smoker

A current daily smoker is a respondent who reported at the time of interview that they regularly smoked one or more cigarettes, cigars or pipes per day. See also Smoker status.

#### Diabetes mellitus

A chronic condition in which blood glucose levels become too high due to the body producing little or no insulin, or not responding to insulin properly.

Data on diabetes refers to persons who reported having been told by a doctor or nurse that they had diabetes (including persons who were not ever told or not known), irrespective of whether the person considered their diabetes to be current or long-term. This definition was first used for estimates of diabetes in Australian Health Survey: Updated Results, 2011-12 (cat. no. 4364.0.55.003). Estimates of diabetes for all years in the National Health Survey: First Results, 2017-18 (cat. no. 4364.0.55.001), are presented using this definition. In earlier publications prior to National Health Survey: First Results, 2014-15, persons who had reported having diabetes, but that it was not current, were not included.

#### Diastolic blood pressure

Measures the pressure in the arteries as the heart relaxes before the next beat. It is the lower number of the blood pressure reading.

#### Disability status

A disability or restrictive long-term health condition exists if a limitation, restriction, impairment, disease or disorder has lasted, or is expected to last, for six months or more, which restricts everyday activities.

A disability or restrictive long-term condition is classified by whether or not a person has a specific limitation or restriction. The specific limitation or restriction is further classified by whether the limitation or restriction is a limitation in core activities, or a schooling/employment restriction only.

There are five levels of activity limitation (profound, severe, moderate, mild and school/employment restriction only). These are based on whether a person needs help, has difficulty, or uses aids or equipment with any core activities (mobility, self-care and communication). A person's overall level of core activity limitation is determined by their highest level of limitation in any of these activities.

#### Domain

A grouping of conceptually similar individual questions asked in the Health Literacy Questionnaire (HLQ). 44 questions were grouped into nine domains of health literacy.

#### Employed

Persons who had a job or business, or who undertook work without pay in a family business for a minimum of one hour per week. Includes persons who were absent from a job or business. See also Unemployed and Not in the labour force.

#### Equivalised income

Total household income adjusted by the application of an equivalence scale to facilitate comparison of income levels between households of differing size and composition. The 'modified OECD' equivalence scale is used.

#### Exercise

Physical activity (exercise only) which consists of four domains, walking for transport, walking for fitness, sport or recreation, moderate exercise and vigorous exercise, which was undertaken in the last week.

#### Family composition of household

Refers to the composition of the household to which the respondent belongs to. In this publication households are categorised as persons living alone, couple only, couple with child(ren), and other households.

#### Healthcare providers

Doctors, nurses, physiotherapists, dieticians and any other health worker survey respondents seek advice or treatment from.

#### Health literacy

The ability of individuals to gain access to, understand and use information in ways which promote and maintain good health.

#### Health literacy questionnaire (HLQ)

A multi-dimensional health literacy assessment tool for surveys, evaluation and service improvement. It focuses on collecting information about the inclusive and equitable access to health information that empowers people to undertake action to improve their own health, as well as the health of their families and communities.

#### Health literacy score

A summary statistic expressed as the mean of the values for each health literacy domain, falling within a range of 1-4 or 1-5 depending on the domain.

#### Health risk factors

Specific lifestyle and related factors impacting on health, including:

• Tobacco smoking;
• Alcohol consumption;
• Exercise;
• Body Mass Index;
• Blood pressure.

#### Heart, stroke and vascular conditions (heart disease)

In the National Health Survey: First Results, 2017-18 (cat. no. 4364.0.55.001), data on heart, stroke and vascular disease refers to persons who reported having been told by a doctor or nurse that they had any of a range of circulatory conditions comprising:

• Ischaemic heart diseases (angina, heart attack and other ischaemic heart diseases);
• Cerebrovascular diseases (stroke and other cerebrovascular diseases);
• Oedema;
• Heart failure; and
• Diseases of the arteries, arterioles and capillaries,

and that their condition was current and long-term; that is, their condition was current at the time of interview and had lasted, or was expected to last, 6 months or more.

However, all persons who reported having ischaemic heart diseases cerebrovascular diseases, heart failure and rheumatic heart disease are included, even if they were not reported to be current and long-term at the time of interview. These conditions are automatically considered to be current and long term. Estimates of heart, stroke and vascular disease for 2007-08, 2011-12, 2014-15 and 2017-18 in this publication are presented using this definition. There is limited comparability between 2007-08 and previous years due to a change in derivation methodology in 2007-08.

#### High blood pressure

In the National Health Survey 2017-18, persons aged 18 years and over could consent to having a blood pressure measurement taken at the time of the interview. Participants who recorded a systolic blood pressure reading 140mmHg or greater were counted as having a high blood pressure reading. Note that this only referred to the measurement at the time of the interview and does not necessarily indicate a chronic condition. For this survey, this is distinguished from 'Hypertension' which was self reported as a long term health condition.

#### Household

A household is defined as one or more persons, at least one of whom is at least 15 years of age, usually resident in the same private dwelling. In this survey, only households with at least one adult (aged 18 years and over) were included.

#### Hypertension

Hypertension (commonly known as high blood pressure) is a condition in which blood pressure in the arteries is elevated, requiring the heart to work harder than normal to circulate blood throughout the body. Hypertension is a major risk factor for hypertensive heart disease, strokes, myocardial infarction (heart attacks) and chronic kidney disease as well as several other medical conditions.

Information on hypertension/high blood pressure was collected in the National Health Survey using two methods. These were:

• a question on whether respondents had ever been told by a doctor or nurse they had any circulatory conditions (including hypertension or high blood pressure), and
• for adults aged 18 years and over, the taking of blood pressure measurements. A person was defined as having high blood pressure if their systolic/diastolic blood pressure was equal to or greater than 140/90 mmHg. Numbers of people with measured high blood pressure do not include people who have high blood pressure but are managing their condition through the use of blood pressure medications.

In the National Health Survey 2017-18, the term 'Hypertension' refers specifically to respondents who had ever been told by a doctor or nurse that they had hypertension or high blood pressure, and does not relate to the voluntary blood pressure measurement.

#### ICD-10

ICD-10 refers to the tenth revision of the International Classification of Diseases and Health Related Problems. The classification of long-term conditions most commonly used in output from the 2017-18 NHS was developed for use in this survey based on the ICD-10.

#### Index of relative socio-economic disadvantage

This is one of four Socio-Economic Indexes for Areas (SEIFA) compiled by ABS following each Census of Population and Housing. The indexes are compiled from various characteristics of persons resident in particular areas: the Index of Relative Socio-Economic Disadvantage summarises attributes such as low income, low educational attainment, high unemployment and jobs in relatively unskilled occupations. A lower Index of Relative Socio-Economic Disadvantage quintile (e.g. the first quintile) indicates relatively greater disadvantage and a lack of advantage in general. A higher Index of Relative Socio-Economic Disadvantage (e.g. the fifth quintile) indicates a relative lack of disadvantage and greater advantage in general. For further information about the indexes, see Census of Population and Housing: SEIFA, Australia.

#### Ischaemic heart disease

A disease of the blood vessels supplying the heart muscle.

#### Items

Health literacy information collected through individual questions in the Health Literacy Questionnaire (HLQ). For example, "I spend quite a lot of time actively managing my health".

#### Kidney disease

A subset of symptoms including: problems or complaints about the kidneys, renal pain and renal colic (kidney stones).

#### Level of highest educational attainment (ASCED)

An Australian standard classification that provides a basis for comparable administrative and statistical data on educational activities and attainment classified by level and field.

#### Long-term health condition

A medical condition (illness, injury or disability) which has lasted at least six months, or which the respondent expects to last for six months or more. Some reported conditions were assumed to be long-term, including asthma, arthritis, cancer, osteoporosis, diabetes, sight problems, rheumatic heart disease, heart attack, angina, heart failure and stroke. Diabetes, rheumatic heart disease, heart attack, angina, heart failure and stroke were also assumed to be current.

#### Margin of error (MoE)

Margin of Error describes the distance from the population value that the sample estimate is likely to be within, and is specified at a given level of confidence. Confidence levels typically used are 90%, 95% and 99%. For example, at the 95% confidence level the MoE indicates that there are about 19 chances in 20 that the estimate will differ by less than the specified MoE from the population value (the figure obtained if all dwellings had been enumerated). For further information see Technical Note and Data Quality.

#### Mental and behavioural conditions

Includes organic mental problems, alcohol and drug problems, mood (affective) disorders such as depression, anxiety related problems and other mental and behavioural problems.

#### Not in the labour force

Persons who are not employed or unemployed as defined, including persons who:

• Are retired;
• No longer work;
• Do not intend to work in the future;
• Are permanently unable to work; or
• Have never worked and never intend to work.

#### Osteoporosis

A condition that thins and weakens bone mineral density, generally caused by loss of calcium, which leads to increased risk of fracture.

#### People

In this publication, people refers to adults aged 18 years and over.

#### Physical activity

Refers to exercise only. The 2014 Physical Activity Guidelines are based on Australia’s Physical Activity and Sedentary Behaviour Guidelines.

#### Psychological distress

Derived from the Kessler Psychological Distress Scale (K10). This is a scale of non-specific psychological distress based on 10 questions about negative emotional states in the past 30 days. The K10 is scored from 10 to 50, with higher scores indicating a higher level of distress; low scores indicate a low level of distress. In this publication, scores are grouped as follows:

• Low levels of distress (10-15);
• Moderate levels of distress (16-21);
• High levels of distress (22-29); and
• Very high levels of distress (30-50).

#### Self-assessed health status

A person's general assessment of their own health against a five point scale from excellent through to poor.

#### Significance testing

To determine whether a difference between two survey estimates is a real difference in the populations to which the estimates relate, or merely the product of different sampling variability, the statistical significance of the difference can be tested. This is particularly useful for interpreting apparent changes in estimates over time. The test is done by calculating the standard error of the difference between two estimates and then dividing the actual difference by the standard error of the difference. If the result is greater than 1.96, there are 19 chances in 20 that there is a real difference in the populations to which the estimates relate. For further information see Data Quality.

#### Smoker status

Refers to the frequency of smoking of tobacco, including manufactured (packet) cigarettes, roll-your-own cigarettes, cigars and pipes, but excluding chewing tobacco, electronic cigarettes (and similar) and smoking of non-tobacco products. Categorised as:

• Current daily smoker - a respondent who reported at the time of interview that they regularly smoked one or more cigarettes, cigars or pipes per day;
• Current smoker - Other - a respondent who reported at the time of interview that they smoked cigarettes, cigars or pipes, less frequently than daily;
• Ex-smoker - a respondent who reported that they did not currently smoke, but had regularly smoked daily, or had smoked at least 100 cigarettes, or smoked pipes, cigars, etc at least 20 times in their lifetime; and
• Never smoked - a respondent who reported they had never regularly smoked daily, and had smoked less than 100 cigarettes in their lifetime and had smoked pipes, cigars, etc less than 20 times.

#### Socio-economic indexes for areas (SEIFAs)

Four Indexes compiled by the ABS following each population Census. Each index summarises different aspects of the socio-economic condition of areas. The Index of Disadvantage is the SEIFA index most frequently used in health analysis.

The Indexes available for use with 2017-18 NHS data are those compiled from the 2016 Census of Population and Housing. For further information about the indexes, see Census of Population and Housing: SEIFA, Australia.

#### Systolic blood pressure

Measures the pressure in the arteries as the heart pumps blood during each beat. It is the higher number of the blood pressure reading.

#### Unemployed

Persons aged 15 years and over who were not employed and actively looking for work in the four weeks prior to the survey, and were available to start work in the week prior to the survey.

#### Usual daily intake of fruit

Refers to the number of serves of fruit (excluding drinks and beverages) usually consumed each day, as reported by the respondent. A serve is approximately 150 grams of fresh fruit or 50 grams of dried fruit. Adequate daily fruit intake refers to whether the respondent met the minimum number of serves as recommended in the NHMRC 2013 Australian Dietary Guidelines. Juices were excluded.

#### Usual daily intake of vegetables

Refers to the number of serves of vegetables (excluding drinks and beverages) usually consumed each day, as reported by the respondent. A serve is approximately half a cup of cooked vegetables (including legumes) or one cup of salad vegetables - equivalent to approximately 75 grams. Adequate daily vegetable intake refers to whether the respondent met the minimum number of serves as recommended in the NHMRC 2013 Australian Dietary Guidelines. Tomatoes were included as vegetables while juices were excluded.

Age group (years)
Recommended serves per day2-314-1819-5051-7070 years and over
Fruit
Males12222
Females12222
Vegetables
Males2.55.565.5(a)5
Females2.55555

a. Rounded up to 6 serves in published data.