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4324.0.55.001 - Microdata: Australian Health Survey, National Health Survey, 2011-12 Quality Declaration 
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 13/11/2014   
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This document was added 04/10/2014.



USING THE TABLEBUILDER

Note on Continuous Items
Confidentiality features in TableBuilder
Weight Variables
Means and Medians
Items on multiple levels
Persons in Household vs Person variables

Instructions on how to use the TableBuilder can be found here User Manual: TableBuilder, Jun 2013 (cat. no. 1406.0.55.005) and via the help links within the product itself.

For support in the use of TableBuilder and analysis of the data generated from the TableBuilder, please contact Microdata Access Strategies on 02 6252 7714 or via microdata.access@abs.gov.au.

For confidentiality and/or usability reasons some data item values have been collapsed and/or restricted for use on the TableBuilder.

NOTE ON CONTINUOUS ITEMS

Some continuous data items are allocated special codes for certain responses (e.g. 9999 = 'Not applicable'). When creating ranges for such continuous items for use in the TableBuilder, these special codes will NOT be included in these ranges (any special codes for continuous (summation) data items are listed in the Data Item List and will be found in the categorical version of the continuous item. However, note that labelling of 0s in the DIL does not necessarily mean they are excluded from the ranges (for example - identifying 0 as 'Did not visit' or 'Did not do') as they may still be important in some calculations. Reference should be made to the categorical version of the item to identify which codes are specifically excluded). Therefore the total shown only represents 'valid responses' of that continuous data item rather than all responses (including special codes).

For example:

Systolic Blood Pressure is located both in the Person level folder....
Image of the location of 'Systolic Blood Pressure in the Person Level folder

and the Summation Options.

Image of the location of 'Systolic Blood Pressure' in the Summation Options Person Level folder

The following table shows the responses for 'Systolic Blood Pressure' by 'Sex of person' as it appears in the version in the Person level folder. The continuous values of the data item are contained in the 'A valid response was recorded' row. If the actual continuous values are to be displayed then it is necessary to create a range for them using the Summation Options version..

Image of table results of 'Systolic Blood Pressure' (Person Level folder versions) by 'Sex of Person'

Here is the same table with a range applied for the continuous (summation) values of 'Systolic Blood Pressure' (Systolic range). Note that the numbers of respondents for the other responses 'Not applicable', 'Valid reading not obtained' and 'Not measured' no longer contribute to the table.

Image of table results of 'Systolic Blood Pressure' by 'Systolic Blood Pressure' (Ranged Summation version) by 'Sex of Person'

Continuous items can be used to create custom categories in 'My Custom Data' by first ranging the item. For example, to create five year age groupings this can be done by ranging the item with a five year increments from Summation Options. However to deviate from from groupings of equal increments, this must be done in 'My Custom Data'. As age is a continuous item, for deviations from equal increments, it must first be ranged (for example in one year increments) and then this ranged item can be grouped under the 'My Custom Data' tab to form unique age categories. For more information see the 'My Custom Data' section of the User Manual: TableBuilder, Jun 2013 (cat. no. 1406.0.55.005).

CONFIDENTIALITY FEATURES IN TABLEBUILDER

In accordance with the Census and Statistics Act 1905, all the data in TableBuilder are subjected to a confidentiality process before release. This confidentiality process is undertaken to avoid releasing information that may allow the identification of particular individuals, families, households, dwellings or businesses.

Processes used in TableBuilder to confidentialise records include the following:

  • perturbation of data
  • table suppression
  • field exclusion groups

Perturbation Effects

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 adjustments 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.

The introduction of these random adjustments result in tables not adding up. While some datasets apply a technique call additivity to give internally consistent results, additivity has not been implemented on this TableBuilder. As a result, randomly adjusted individual cells will be consistent across tables, but the totals in any table will not be the sum of the individual cell values. The size of the difference between summed cells and the relevant total will generally be very small.

Please be aware that the effects of perturbing the data may result in components being larger than their totals. This includes determining proportions.

Table suppression

Some tables generated within TableBuilder may contain a substantial proportion of very low counts within cells (excluding cells that have counts of zero). When this occurs, all values within the table are suppressed in order to preserve confidentiality. The following error message below is displayed at the bottom of the table when table suppression has occurred.

ERROR: The table has been suppressed as it is too sparse
ERROR: table cell values have been suppressed

Field exclusion rules

Certain groups of similar variables are restricted from being used together in a table. These restrictions are referred to as field exclusion rules, and are in place in order to protect confidentiality. The collections of similar variables restricted in this way are called field exclusion groups.

For the Australian Health Survey, there is one field exclusion group. This consists of the 2006 and 2011 geographical and Socio-Economic Indexes for Areas (SEIFA) data items (see below for items).

Only one data item from this group may be used in a single table.

The geographic exception to this is the State or Territory item, which can be used in addition to one item from this group.

Items included in the field exclusion group are:

2006 Geographic Items

  • ASGC remoteness area categories
  • Capital city and balance of state
  • Section of state

2011 Geographic Items
  • Remoteness area categories ASGS 2011
  • Greater Capital City Statistical Areas ASGS 2011
  • Section of state ASGS 2011
  • Medicare Locals
  • Peer Groups (MLs)

2006 SEIFA Items
  • Index of Economic Resources - 2006 - CD - Deciles - National
  • Index of Economic Resources - 2006 - CD - Deciles - State
  • Index of Economic Resources - 2006 - SLA - Deciles - National
  • Index of Economic Resources - 2006 - SLA - Deciles - State
  • Index of Education and Occupation - 2006 - CD - Deciles - National
  • Index of Education and Occupation - 2006 - CD - Deciles - State
  • Index of Education and Occupation - 2006 - SLA - Deciles - National
  • Index of Education and Occupation - 2006 - SLA - Deciles - State
  • Index of Relative Socio-economic Advantage and Disadvantage - 2006 - CD - Deciles - National
  • Index of Relative Socio-economic Advantage and Disadvantage - 2006 - CD - Deciles - State
  • Index of Relative Socio-economic Advantage and Disadvantage - 2006 - SLA - Deciles - National
  • Index of Relative Socio-economic Advantage and Disadvantage - 2006 - SLA - Deciles - State
  • Index of Relative Socio-economic Disadvantage - 2006 - CD - Deciles - National
  • Index of Relative Socio-economic Disadvantage - 2006 - CD - Deciles - State
  • Index of Relative Socio-economic Disadvantage - 2006 - SLA - Deciles - National
  • Index of Relative Socio-economic Disadvantage - 2006 - SLA - Deciles - State

2011 SEIFA Items
  • Index of Economic Resources - 2011 - SA1 - Deciles - National
  • Index of Economic Resources - 2011 - SA1 - Deciles - State
  • Index of Economic Resources - 2011 - SA2 - Deciles - National
  • Index of Economic Resources - 2011 - SA2 - Deciles - State
  • Index of Education and Occupation - 2011 - SA1 - Deciles - National
  • Index of Education and Occupation - 2011 - SA1 - Deciles - State
  • Index of Education and Occupation - 2011 - SA2 - Deciles - National
  • Index of Education and Occupation - 2011 - SA2 - Deciles - State
  • Index of Relative Socio-economic Advantage and Disadvantage - 2011 - SA1 - Deciles - National
  • Index of Relative Socio-economic Advantage and Disadvantage - 2011 - SA1 - Deciles - State
  • Index of Relative Socio-economic Advantage and Disadvantage - 2011 - SA2 - Deciles - National
  • Index of Relative Socio-economic Advantage and Disadvantage - 2011 - SA2 - Deciles - State
  • Index of Relative Socio-economic Disadvantage - 2011 - SA1 - Deciles - National
  • Index of Relative Socio-economic Disadvantage - 2011 - SA1 - Deciles - State
  • Index of Relative Socio-economic Disadvantage - 2011 - SA2 - Deciles - National
  • Index of Relative Socio-economic Disadvantage - 2011 - SA2 - Deciles - State

WEIGHT VARIABLES

There are three weight variables visible on the file:
  • Households (Benchmarked weight) - located on the Household level. This weight has been benchmarked to produce Australian household estimates.
  • Persons (Benchmarked weight) - located on the Person level. This weight has been benchmarked to produce Australian population estimates.
  • Biomedical persons (Benchmarked weight) - located on the Biomedical level. Biomedical participants have been weighted and benchmarked to produce Australian population estimates for persons 5 years and over. For more details on this weight, see below.

Using Weights

The NHS is a sample survey. To produce estimates for the in-scope population you must use weight fields in your tables. In TableBuilder they can be found under the Summation Options category in the left hand pane under the applicable level. If you do not select a weight field, TableBuilder will apply 'Persons (Benchmarked weight)' by default. This will give you estimates of the number of persons. To produce estimates of the number of households you would have to add Households (Benchmarked weight) from the Household level to your table. To produce estimates for NHS selected persons who participated in the National Health Measures Survey (NHMS), the Biomedical persons (Benchmarked weight) located on the Biomedical level must be used.

Note that when dealing with the functions of means, medians, and sums, a weight is automatically applied from a weight allocated behind the scenes to the level of the variable (for all levels, other than Persons in household, a person weight has been applied to each record (e.g. alcohol record) on the level based on the weight allocated to selected persons on the Person level. For Persons in household, the household weight has been applied to each person in the household). These weights are not visible but are referenced in the 'Weighted by' statement with continuous variables, as per:

Image of 'Volume of type of drink consumed (mls) by type of drink' located in Summations options
For more details, see Means and Medians below.

When using a Weight/Summation from a level that is different to that of the variables in the table please be careful in interpreting the results.

LEVELSESTIMATES IF USE HOUSEHOLD WEIGHTSESTIMATES IF USE PERSON WEIGHTS
Household levelHouseholds with the specified characteristics.Persons with the specified household characteristics (based on selected person).
Persons in Household levelHouseholds containing one or more persons with the specified characteristics.Persons in households containing one or more persons with the specified characteristics.
Person levelHouseholds containing one or more selected persons with the specified characteristics.Persons with the specified characteristics.
Alcohol Day levelHouseholds containing one or more selected persons with one or more alcohol days with the specified characteristics.Persons with one or more alcohol days with the specified characteristics.
Alcohol Type levelHouseholds containing one or more selected persons with one or more types of alcohol drunk on at least one day with the specified characteristics.Persons with one or more alcohol types on at least one day with the specified characteristics.
Actions level (Condition Group)Households containing one or more selected persons with one or more conditions related to an actions group with the specified characteristics.Persons with one or more conditions related to an actions group with the specified characteristics.
Condition levelHouseholds containing one or more selected persons with one or more conditions with the specified characteristics.Persons with one or more conditions with the specified characteristics.
Medication level Households containing one or more selected persons with one or more medications with the specified characteristics.Persons with one or more medications with the specified characteristics.
Biomedical levelHouseholds containing one or more selected biomedical persons with specified characteristics.Use Biomedical weight to calculate persons with specified characteristics.


Note that the Biomedical level also contains non-biomedical participant records, however their biomedical weight is set to 0 so they will not contribute to estimates when the Biomedical persons (Benchmarked weight) is used. However, if the Persons (Benchmarked weight) is used with biomedical data items then these non-participants will contribute to estimates. When using biomedical variables in conjunction with other variables on the biomedical level or with variables from other levels, the Biomedical persons (Benchmarked weight) should be used.

For example, a table of reported fasting status using the 'Persons (Benchmarked weight)' will show the fasting status for the entire NHS survey. Note that the 'Not applicable' persons include those people who did not participate in the NHMS and those persons aged 5 to 11 years who participated in the NHMS but were only required to provide a urine sample. The population for this table represents the entire Australian population.

Image of table of Fasting status using Persons (Benchmarked weight)

The same table using the 'Biomedical persons (Benchmarked weight)' will show the fasting status for only persons who participated in the NHMS. Note that in this case, 'Not applicable' persons are those people aged 5 to 11 years who participated in the NHMS but were only required to provide a urine sample. People who did not participate in the biomedical component do not have a biomedical person weight and therefore do not contribute to the table when this weight is used. The biomedical population now presents weighted estimates for the Australian population aged 5 years and over.

Image of table of Fasting status using Biomedical persons (Benchmarked weight)


MEANS AND MEDIANS

Means and medians of continuous data items are calculated at the level of the continuous data item and therefore use the weight at that level. Due to current functionality of the software, a weight from another level cannot be brought into such calculations. The "subject" of the means and medians calculated in TableBuilder is therefore the statistical unit associated with the level of the database on which the continuous data item is stored. For example, the mean of the "Mls of pure alcohol consumed by day" data item at the the Alcohol Day level would give the mean total volume of pure alcohol per day while the mean of "Mls of pure alcohol consumed by type of drink" data item at the Alcohol Type level would be the mean total mls of pure alcohol per alcohol type (or per alcohol type by day if desired).

ITEMS LOCATED ON MULTIPLE LEVELS

Where items are available on more than one level, an additional number is added to the label to indicate the level version. For example a (1) indicates it's a Household level version, a (2) indicates a Persons in household level version, a (3) indicates a Person level version, and so on. These are identified in the Data item list labelling as well as the item in TableBuilder. The numbering is based on the ordering of levels found in the File Structure page of this product.

Care should be used to ensure the correct version of the item is used, particularly with regards to demographic items located on both the Persons in household and Person levels. See below for more details.

PERSONS IN HOUSEHOLD VS PERSON VARIABLES

The Persons in Household level contains data for every person in the household while the Persons level only contains data for the selected persons. Both levels are children of the Household level - that is, they are siblings and are not linked by person but by household. This means that there is a many-to-many link between records at these levels (persons on the Person level are linked to all the people in their household on the Persons in household level). The Persons in Household level is available in order to produce compositional information about the household (e.g. Whether there are persons in the household aged 4-14 years) which can then either be used with the household weight to represent for example the the number of households which contain persons aged 4-14 years, or with the person weight to represent the number of people living in household that contain persons aged 4-14 years.

When summing the Persons (Benchmarked weight) (which is stored at the Person level) the meaning of the estimates produced when disaggregating by another data item at the Person level will not be the same as the meaning of the estimates produced when disaggregating by a data item at the Persons in Household level. For example, disaggregating by Sex of person (3) and Registered marital status (3) from the Person level will produce estimates of the "Number of persons who are Male and Married". These estimates will be additive (aside from the effects of perturbation) as shown below.

Image of table of Sex of Person (Person level) by Marital Status (Person level)

On the other hand, disaggregating by Sex of person (2) and Registered marital status (2) from the Persons in Household level, and using the Persons (Benchmarked weight) from the Person level, will produce estimates of the type "Number of persons living in households containing one or more persons who are Male and Married". These estimates will usually not be additive as shown below.

Image of table of Sex of Person (Persons in Household level) by Marital Status (Persons in Household level)

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