Data confidentiality
Introduction
9.1 This chapter outlines how international merchandise trade statistics are confidentialised prior to their release. It explains the legal basis for confidentiality, the types of restrictions that are imposed, the effect of confidentiality on the statistics produced and the procedures used to manage confidentiality.
Legal basis to confidentiality
9.2 The vast majority of ABS data are collected under the Census and Statistics Act 1905 (C&S Act). The C&S Act empowers the ABS to direct persons, businesses and other entities to provide the data requested. As such, the ABS has procedures in place to protect the identity of data providers. This enables and maintains public trust in the ABS and high quality national statistics.
9.3 The confidentiality of the data collected is protected by provisions in the C&S Act which prescribe the manner in which statistical information can be disclosed. Section 12 of the C&S Act prohibits publication or dissemination of statistics "in a manner that is likely to enable the identification of a particular person or organisation". In relation to international merchandise trade statistics, subsection 12(2) makes provision for the protection of confidential data.
9.4 The Census and Statistics (Information Release and Access) Determination 2018 supports the C&S Act by specifying the particular circumstances under which the disclosure of identifiable statistical information is allowed.
9.5 This means that international merchandise trade statistics, unlike most other statistics released by the ABS, are subject to "passive confidentiality" i.e. statistics are able to be released without explicit regard to confidentiality, unless and until a business or organisation demonstrates that such disclosure would be likely to enable the identification of that business or organisation.
9.6 The Australian Statistician has given approval in writing to release international merchandise trade statistics under the Census and Statistics (Information Release and Access) Determination 2018.
Types of confidentiality restrictions and their impact on international merchandise trade statistics
9.7 The ABS recognises that detailed commodity statistics for exported and imported goods play an important role in the analysis of Australia's trade with the rest of the world. However, this need for detailed information has to be balanced with an individual's or organisation's entitlement to data confidentiality. Where a confidentiality restriction is required, the ABS determines the lowest form of restriction which satisfies their legal entitlement, while maximising the utility of statistical information.
9.8 A variety of restrictions are available to protect the confidentiality of an individual's or organisation's data. Each type of restriction is designed to protect a particular aspect of the data. Restrictions are placed at the commodity level, and the information is restricted for all trade in that commodity, not just that relating to the particular individual or organisation which requested the restriction.
Current confidentiality restrictions
9.9 The various confidentiality restrictions, and their impact on international merchandise trade statistics, are set out in Table 9.1 below.
| Type of restriction | How the restriction affects statistics |
|---|---|
| No Commodity Details | Under the most comprehensive restriction able to be applied, no data relating to a particular commodity are released. Instead, in statistics classified by commodity, the data are included in a commodity code together with data for all other commodities that are similarly restricted. The confidential commodity codes used for the presentation of the most detailed data are shown in Table 9.2. From September 2008 for Imports and June 2013 for Exports, at the total level, this data is not split back to individual country, state or ports and is shown as 'Country not available for publication' and similarly with state and ports. |
| Broad Commodity Details | Like the 'No Commodity Details' restriction, the 'Broad Commodity Details' restriction also prevents the release of commodity detail, but allows data to be released at the broad commodity level, without that level being impacted by the restriction. Under this restriction, data for a group of confidential commodities in the same area of the classification are combined and presented in a single item within the relevant area (chapter) of the classification. This restriction is only used in two cases: exports of metalliferous ores (Harmonised System chapter 26), from July 1990 onwards; and, imports of organic chemicals (Harmonised System chapter 29), from July 1991 onwards. This means that the aggregated data for exports in HS chapter 26 and imports in HS chapter 29 provide the correct value. |
| No Country Details | Under this restriction, no details of the country of origin (for imports) or the country of final destination (for exports) are made available for a particular commodity. Information relating to overseas ports is also suppressed. |
| Selected Country Details | Under this restriction selected countries have the country of origin (for imports) or the country of final destination (for exports) suppressed. Instead of combining the details with data for all other countries having a similar restriction (as the 'No Country Details' restriction does) this restriction suppresses details for a group of countries, but presents full details for other countries. Where information relating to a country is suppressed, information relating to ports in that country is also suppressed. |
| No State Details | Under this restriction, export and import commodity statistics classified by Australian state are not made available. Information relating to Australian ports is also not available. |
| Selected State Details | This restriction suppresses commodity details that are confidential for one or more Australian state(s), by combining details for states with details for one or more other states. Information relating to Australian ports for the selected states are also suppressed. Details for the remaining states are made available in the normal way. |
| No Quantity Details | Under this restriction the value of trade in the commodity is available, but quantity and gross weight are suppressed. |
| No Value Details | For commodities subject to this restriction, the quantity and gross weight of the commodity are available, but value is suppressed. From September 2008 for Imports and June 2013 for Exports, at the total level these value data are not split back to individual country, state or ports and are shown as 'Country not available for publication' and similarly with state and ports. |
| No Value for Country Details | This restriction suppresses value details by country for the particular commodity to which it applies. Quantity details by country are available, but value is allocated to the category 'No Country Details'. |
| No Duty Details | This restriction is only relevant to import clearances and can only be used in conjunction with a country restriction. The 'No Duty Details' restriction results in the suppression of all duty details (rate of duty, nature of tariff, treatment code, preference code and duty paid) for statistics where country has been suppressed. Whenever a restriction is placed on a country ('No Country Details', 'Selected Country Details'), a 'No Duty Details' restriction is automatically applied. |
Note: Restrictions other than 'No Commodity Details' and 'Broad Commodity Details' can be combined. For example 'Selected Country Details', 'No State Details' and 'No Duty Details'. See Table 9.4 for the most commonly used combined restrictions and their impact on statistical outputs.
| Classification | Code | Description |
|---|---|---|
| AHECC | 99999999 | Combined confidential items: from July 1990 on, excluding HS Chapter 26 codes confidentialised with Broad Commodity Details restrictions |
| Customs Tariff | 9988888899 | Combined confidential items: from July 1991 on, excluding HS Chapter 29 codes confidentialised with Broad Commodity Details restrictions, likewise Chapter 28 Broad Commodity Details, excepting that these ceased after December 1994 |
| SITC Revision 4 | 98888 | Combined confidential items excluding some of SITC 28099 (exports only) and some of SITC 51099 (imports only) |
| ANZSIC 2006 | 9899 | Sum of confidential items not more specifically classified |
| BEC | 700 | Goods not elsewhere specified (including confidential items) |
| BoPBEC | ON02 | Other goods nes |
- The confidential commodity codes listed in this table are those which are shown in tables containing the most detailed data possible for the classification. That is, a table of export data showing 8-digit AHECC information would include an aggregate of all commodities affected by the no commodity details restriction under the commodity code 99999999. A table showing 4-digit AHECC information would include an aggregate of all commodities affected by the no commodity details restriction under the commodity code 9999.
Impact of confidentiality restrictions on international merchandise trade statistics
9.10 Table 9.3 below compares the impact of the different types of restriction on statistical output classified by country and state. The first column shows the data as it would appear in output (both quantity and value) if there were no confidentiality restrictions and each of the other nine columns shows the impact a different type of confidentiality restriction would have on output of the same data.
| Type of Restriction | 1 | 2 | 3 | 4 | 5 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| No Restrictions | No Commodity Details | Broad Commodity Details | No Country Details | Selected Country Details (Malaysia, Taiwan) | |||||||
| Example: Commodity at the most detailed level | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | |
| Total this item | |||||||||||
| Total states | Y | Y | – | – | – | – (a) | Y | Y | Y | Y | |
| Victoria | Y | Y | – | – | – | – | Y | Y | Y | Y | |
| Queensland | Y | Y | – | – | – | – | Y | Y | Y | Y | |
| Western Australia | Y | Y | – | – | – | – | Y | Y | Y | Y | |
| No State Details | na | na | – | – | – | – | na | na | na | na | |
| Malaysia | |||||||||||
| Total States | Y | Y | – | – | – | – | – | – | – | – | |
| Victoria | Y | Y | – | – | – | – | – | – | – | – | |
| Queensland | Y | Y | – | – | – | – | – | – | – | – | |
| Western Australia | Y | Y | – | – | – | – | – | – | – | – | |
| No State Details | na | na | – | – | – | – | – | – | – | – | |
| Singapore | |||||||||||
| Total states | Y | Y | – | – | – | – | – | – | Y | Y | |
| Victoria | Y | Y | – | – | – | – | – | – | Y | Y | |
| Queensland | Y | Y | – | – | – | – | – | – | Y | Y | |
| Western Australia | Y | Y | – | – | – | – | – | – | Y | Y | |
| No State Details | na | na | – | – | – | – | – | – | na | na | |
| Taiwan | |||||||||||
| Total states | Y | Y | – | – | – | – | – | – | – | – | |
| Victoria | Y | Y | – | – | – | – | – | – | – | – | |
| Queensland | Y | Y | – | – | – | – | – | – | – | – | |
| Western Australia | Y | Y | – | – | – | – | – | – | – | – | |
| No State Details | na | na | – | – | – | – | – | – | – | – | |
| No country details | |||||||||||
| Total states | na | na | – | – | – | – (a) | Y | Y | Y | Y | |
| Victoria | na | na | – | – | – | – | Y | Y | Y | Y | |
| Queensland | na | na | – | – | – | – | Y | Y | Y | Y | |
| Western Australia | na | na | – | – | – | – | Y | Y | Y | Y | |
| No State Details | na | na | – | – | – | – | na | na | na | na | |
– Data not published - Confidentiality restriction has been applied
na Data is not applicable in these categories as it is included in other categories (e.g. there is no data published in 'No State Details' category if data is published in the individual state category)
- For the example of a commodity at the most detailed level, the same data are releasable under the 'Broad Commodity Details' and 'No Commodity Details' restrictions (i.e. no data published). However, in a table showing all 2 digit commodities, the 'Broad Commodity Details' combined item would show a value in the 'Total this item' and 'No Country Details' but no values would be published for commodities affected by a 'No Commodity Details' restriction. For a description of the different confidentiality restrictions see Table 9.1.
Y Data published - Confidentiality restriction not applicable
| Type of Restriction | 6 | 7 | 8 | 9 | 10 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| No State Details | Selected State Details (QLD, WA) | No Quantity Details | No Value Details | No Value Details by Country | |||||||
| Example: Commodity at the most detailed level | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | |
| Total this item | |||||||||||
| Total states | Y | Y | Y | Y | – | Y | Y | – | Y | Y | |
| Victoria | – | – | Y | Y | – | Y | Y | – | Y | Y | |
| Queensland | – | – | – | – | – | Y | Y | – | Y | Y | |
| Western Australia | – | – | – | – | – | Y | Y | – | Y | Y | |
| No State Details | Y | Y | Y | Y | – | na | na | – | na | na | |
| Malaysia | |||||||||||
| Total States | Y | Y | Y | Y | – | Y | Y | – | Y | – | |
| Victoria | – | – | Y | Y | – | Y | Y | – | Y | – | |
| Queensland | – | – | – | – | – | Y | Y | – | Y | – | |
| Western Australia | – | – | – | – | – | Y | Y | – | Y | – | |
| No State Details | Y | Y | Y | Y | – | na | na | – | na | – | |
| Singapore | |||||||||||
| Total states | Y | Y | Y | Y | – | Y | Y | – | Y | – | |
| Victoria | – | – | Y | Y | – | Y | Y | – | Y | – | |
| Queensland | – | – | – | – | – | Y | Y | – | Y | – | |
| Western Australia | – | – | – | – | – | Y | Y | – | Y | – | |
| No State Details | Y | Y | Y | Y | – | na | na | – | na | – | |
| Taiwan | |||||||||||
| Total states | Y | Y | Y | Y | – | Y | Y | – | Y | – | |
| Victoria | – | – | Y | Y | – | Y | Y | – | Y | – | |
| Queensland | – | – | – | – | – | Y | Y | – | Y | – | |
| Western Australia | – | – | – | – | – | Y | Y | – | Y | – | |
| No State Details | Y | Y | Y | Y | – | na | na | – | na | – | |
| No country details | |||||||||||
| Total states | na | na | na | na | – | na | na | – | na | Y | |
| Victoria | na | na | na | na | – | na | na | – | na | Y | |
| Queensland | na | na | na | na | – | na | na | – | na | Y | |
| Western Australia | na | na | na | na | – | na | na | – | na | Y | |
| No State Details | na | na | na | na | – | na | na | – | na | na | |
– Data not published - Confidentiality restriction has been applied
na Data is not applicable in these categories as it is included in other categories (e.g. there is no data published in 'No State Details' category if data is published in the individual state category)
- For the example of a commodity at the most detailed level, the same data are releasable under the 'Broad Commodity Details' and 'No Commodity Details' restrictions (i.e. no data published). However, in a table showing all 2 digit commodities, the 'Broad Commodity Details' combined item would show a value in the 'Total this item' and 'No Country Details' but no values would be published for commodities affected by a 'No Commodity Details' restriction. For a description of the different confidentiality restrictions see Table 9.1.
Y Data published - Confidentiality restriction not applicable
9.11 Restrictions other than 'No Commodity Details' and 'Broad Commodity Details' can be combined. Table 9.4 below compares the impact of the different types of combined restrictions on statistical output for a commodity classified by country and state. The combined restrictions identified in this table are the most commonly used.
| Type of Restriction | 1 | 2 | 3 | 4 | |||||
|---|---|---|---|---|---|---|---|---|---|
| No Country No State | No Country Selected States (QLD, WA) | Selected Countries (Malaysia, Taiwan) No State | Selected Countries (Malaysia, Taiwan) Selected States (QLD, WA) | ||||||
| Example: Commodity at the most detailed level | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | Quantity (kg) | $'000 | |
| Total this item | |||||||||
| Total states | Y | Y | Y | Y | Y | Y | Y | Y | |
| Victoria | – | – | Y | Y | – | – | Y | Y | |
| Queensland | – | – | – | – | – | – | – | – | |
| Western Australia | – | – | – | – | – | – | – | – | |
| No State Details | Y | Y | Y | Y | Y | Y | Y | Y | |
| Malaysia | |||||||||
| Total States | – | – | – | – | – | – | – | – | |
| Victoria | – | – | – | – | – | – | – | – | |
| Queensland | – | – | – | – | – | – | – | – | |
| Western Australia | – | – | – | – | – | – | – | – | |
| No State Details | – | – | – | – | – | – | – | – | |
| Singapore | |||||||||
| Total states | – | – | – | – | Y | Y | Y | Y | |
| Victoria | – | – | – | – | – | Y | Y | ||
| Queensland | – | – | – | – | – | – | – | – | |
| Western Australia | – | – | – | – | – | – | – | – | |
| No State Details | – | – | – | – | Y | Y | Y | Y | |
| Taiwan | |||||||||
| Total states | – | – | – | – | – | – | – | – | |
| Victoria | – | – | – | – | – | – | – | – | |
| Queensland | – | – | – | – | – | – | – | – | |
| Western Australia | – | – | – | – | – | – | – | – | |
| No State Details | – | – | – | – | – | – | – | – | |
| No country details | |||||||||
| Total states | Y | Y | Y | Y | Y | Y | Y | Y | |
| Victoria | – | – | Y | Y | – | – | Y | Y | |
| Queensland | – | – | – | – | – | – | – | – | |
| Western Australia | – | – | – | – | – | – | – | – | |
| No State Details | Y | Y | Y | Y | Y | Y | Y | Y | |
– Data not published - Confidentiality restriction has been applied
Y Data published - Confidentiality restriction not applicable
Analysing statistics subject to confidentiality restrictions
9.12 Where data are presented on an annual or year-to-date basis, users should take special care when interpreting the data in case there has been a change in confidentiality restrictions during the time period covered.
9.13 For example, if a 'No Country Details' restriction is applied to a commodity for the first half of the year, and lifted for the second half of the year, country classified data for that commodity for the full year will only reflect trade in the second half of the year. Data for the first half of the year will be included in the item 'combined confidential items' of trade in statistics for that country. Complete data will not be presented for trade in the particular item with any individual country, however these data will be included in the individual country and commodity at the total level.
9.14 Users need to be aware that more highly aggregated statistics may also be affected by confidentiality restrictions. Using the example in the previous paragraph, not only will annual country statistics for the specific commodity be incomplete, but statistics for groups of commodities, which include the confidential item, will also be incomplete.
Requests for restrictions
9.15 If an individual or organisation (the claimant) is concerned that the release of international merchandise trade data may identify their activities, they may lodge a request for the data to be suppressed. Anyone considering a request should first obtain a copy of the Information Paper: Request to Confidentialise International Trade Data (cat. no. 5497.0.55.001).
How the ABS handles requests
9.16 After a request for suppression of data has been received, the ABS will investigate the claim in terms of the number of traders and the respective significance of their trade. If the investigation confirms that the business activities of the claimant are likely to be identified an appropriate restriction will be implemented.
9.17 When the appropriate restriction has been chosen, it is generally implemented from the beginning of the next available reference month. Only in exceptional circumstances are restrictions applied to data already processed.
9.18 If the pattern of trade is infrequent, it may be possible to only restrict the data for those months in which the claimant trades. The claimant's concerns can be met for the periods during which it trades, while still releasing useful data for other periods.
Examples of appropriate restrictions
9.19 The restriction that is appropriate to a given situation depends on the extent to which the claimant's activities are identifiable. The following examples illustrate the appropriate restrictions for particular situations:
- If the claimant is identifiable as an importer of commodity X at the Australian level, it would be necessary to suppress all details of imports of commodity X unless the commodity is in a HS chapter where a 'Broad Commodity Details' restriction could be applied.
- If the claimant is identifiable as an importer of commodity X from country Y, it would be necessary to suppress details of the country of origin for imports of commodity X. If a 'Selected Country Details' restriction is sufficient to prevent disclosure it would be applied, otherwise a 'No Country Details' restriction would be applied.
- If the claimant is identifiable as an importer of commodity X into state Z, a 'Selected State Details' restriction (or possibly a 'No State Details' restriction) would be applied.
- If the claimant is identifiable as an importer of commodity X from country Y into state Z, there are several options which would be considered. It may be sufficient to apply a 'Selected State Details', 'No State Details', 'Selected Country Details' or 'No Country Details' restriction, or some combination of these.
Reviews of restrictions
9.20 The application of a restriction for a particular commodity does not mean that it will be applied to all future statistics for that commodity. Once a restriction is put in place, the data remains restricted in all statistics until the restriction is lifted or changed. Restrictions are reviewed periodically to see if they are still warranted in their current form. When changes in trading patterns are identified, a restriction may be lifted completely or amended to suppress more or less data.
9.21 International merchandise trade confidentiality restrictions are reviewed at least every two years. Where the risk of disclosure is marginal, or a restriction has been imposed on the basis of expected trade, a review may be undertaken after a shorter interval, to check whether trading patterns have changed or the expected volumes of trade have occurred. If the data no longer need to be confidentialised, the restriction is lifted from the month following the review. Confidentiality claims are also subject to regular review.
Historical confidentiality restrictions
9.22 The following confidentiality restrictions have been discontinued as output was difficult to interpret. They were phased out as part of the review process from March 2003 onwards.
- No State Details by Selected Country Details - this restriction suppressed trade between all states and the selected countries in the restriction and combined them into a single total. For example (see Table 9.5 below), a 'No State Details by Selected Country Details (UK, USA)' would only suppress State trade in the commodity for the countries UK and USA. This trade would be allocated to a State of 'No State Details' and a country of 'No Country Details'. Trade in the commodity with other countries would be allocated to the correct state. Note that state totals would not include trade for UK and USA.
| China | Singapore | UK | USA | No country details | Total | |
|---|---|---|---|---|---|---|
| NSW | Y | Y | Y(a) | |||
| VIC | Y | Y | Y(a) | |||
| QLD | Y | Y | Y(a) | |||
| No state details | Y(b) | Y(b) | ||||
| Total | Y | Y | Y(b) | Y(c) |
Y Data available - confidentiality restriction not applicable
- Total will include only countries not in selected country list (eg. China and Singapore).
- Total will include total trade for all states for selected countries (eg. UK and USA).
- Total will be correct for commodity code.
- Selected State Details by Selected Country Details - this restriction suppressed only trade between selected states and the selected countries in the restriction and combined them into a single total. For example (see Table 9.6 below), a 'Selected State Details (NSW, VIC) by Selected Country Details (UK, USA)' would suppress trade between states of NSW or Victoria and countries UK and USA. This trade would be allocated to a state of 'No State Details' and a country of 'No Country Details'. Trade in the commodity with other countries would be allocated to the correct state. Note that state totals would not include data for UK and USA and country totals would not contain data for NSW and Victoria.
| China | Singapore | UK | USA | No country details | Total | |
|---|---|---|---|---|---|---|
| NSW | Y | Y | Y(a) | |||
| VIC | Y | Y | Y(a) | |||
| QLD | Y | Y | Y | Y | Y | |
| No state details | Y(b) | Y(b) | ||||
| Total | Y | Y | Y(c) | Y(c) | Y(b) | Y(d) |
Y Data available - confidentiality restriction not applicable
- Total will include only countries not in selected country list (eg. China and Singapore).
- Total will include only states not in selected state list (eg. Queensland).
- Total will include total trade for all states for selected countries (UK and USA) by selected states (New South Wales and Victoria).
- Total will be correct for commodity code.
Confidential Commodities List
9.23 The Confidential Commodities List (CCL) contains information on all commodity based restrictions. The information is presented under the following four headings:
- changes and new restrictions to import items in the current month
- changes and new restrictions to export items in the current month
- all import restrictions from January 1988 to the current month and
- all export restrictions from January 1988 to the current month.
9.24 The following information is provided in the CCL:
- Classification Codes.
- Customs Tariff - the 10 digit code given to an import commodity at the greatest level of detail.
- Australian Harmonised Export Commodity Classification (AHECC) - the 8-digit code given to an export commodity at the greatest level of detail.
- Standard International Trade Classification (SITC) - SITC-Rev. 3 at the 5-digit level for data up to and including June 2005. SITC-Rev. 4 at the 5-digit level from July 2005. CCL codes opening from 1 January 2012 will display 'NA' in the SITC revision 3 column as correspondence to SITC revision 3 is not available. CCL codes closing before 31 December 2001 will display 'NA' in the SITC revision 4 column as correspondence to SITC revision 4 is not available.
- Australian and New Zealand Standard Industrial Classification (ANZSIC) - ANZSIC 1993 at the 4-digit level for data up to June 2009. ANZSIC 2006 at the 4-digit level from July 2005. CCL codes opening from 1 January 2012 will display 'NA' in the ANZSIC 1993 column as correspondence to ANZSIC 1993 is not available. CCL codes closing before 31 December 2001 will display 'NA' in the ANZSIC 2006 column as correspondence to ANZSIC 2006 is not available.
- Deleted Date: indicates that the Customs Tariff or AHECC has been superseded and provides the date this took place. If this field is blank, the Customs Tariff or AHECC is current for the reference period.
- Date of Effect: the month in which the restriction commenced. The date of effect is always the first of the month.
- Date of Cessation: the final month for which a restriction is effective. The date of cessation is always the last day of the month.
- Restriction Applied: type of confidentiality restriction applied.
- Commodity Description: this is an abbreviated description of the goods which are included under the Customs Tariff or AHECC item.
9.25 For those items subject to a 'Selected Country Details', a 'Selected State Details', a 'No State by Country Details', a 'No State by Selected Country Details' or a 'Selected State by Selected Country Details' restriction, the countries or states which are restricted are specified.
9.26 The most recent CCL is available in International Merchandise Trade: Confidential Commodities List (cat. no. 5372.0.55.001),
Non-standard arrangements not reflected in the CCL
Secondary Restriction (AHECC code 28182000)
9.27 A 'No Country Details' restriction was placed on alumina in the 1970s. Because the value of Australia's total exports to some countries are dominated by the trade in alumina, even total trade with the country is considered confidential and is therefore not released separately. For some countries, data for alumina would account for nearly all of the confidential item. The alumina component has therefore been removed from the confidential items for these countries and presented as a single aggregate 'Country Confidential - Alumina'.
9.28 The countries for which this additional or 'secondary' restriction applies are not listed in the CCL. For the period up to and including statistics for February 1992, the countries combined for this 'secondary' restriction were Norway, Egypt and Iceland. From March 1992 until December 2012 (when these secondary restrictions ceased), they were Bahrain, Egypt and Iceland. In addition, exports of Alumina to Bahrain, Egypt and Iceland were excluded from the state totals and included in 'State not available for publication' category.
Port Statistics - Gove and Groote Eylandt
9.29 In some instances there is not sufficient diversity of trade to allow release of data by port. In these cases it is necessary to aggregate data for some ports. In the case of the Northern Territory ports of Gove and Groote Eylandt, details by individual port are suppressed and shown against a 'Confidential Ports - NT' code. This permits accurate totals by state to be released. As the CCL presents details of restrictions by commodity, it does not contain any reference to the restrictions for the ports of Gove and Groote Eylandt.
Confidential data removed from country and state totals
9.30 From September 2008 in imports/clearances and from June 2013 in exports, the method used to confidentialise data changed. Data that have the confidentiality restrictions 'No commodity details' or 'No value details' are aggregated into a single confidential commodity code. For data prior to September 2008 in imports and June 2013 in exports, these data are added back into the relevant state total and country total (i.e. these totals show the correct level of trade).
9.31 From September 2008 in imports/clearances and June 2013 in exports these confidential data are not added back. Instead the confidential data are published as 'No country details' in the country totals and 'State not available for publication' in the state totals. Therefore, country and state totals from September 2008 in imports and June 2013 in exports may not represent the actual amount of trade in each country/state but only the trade in commodities without a 'No commodity details' or 'No value details' restriction. This change to cease adding data back to individual categories but maintaining it in the confidential category applies to mode of transport, port of loading and port of discharge. This change was necessary to ensure the confidentiality of data.
Confidentiality of non-merchandise data for imports
9.32 Additional confidentiality restrictions apply to the non-merchandise trade Customs Tariff item, 9999319902. This code has the following confidentiality restrictions in place: 'No country details', 'No state details', 'No duty details', has been assigned a mode of transport = U (Unknown) and the data has not been added into country or state totals.
Application of confidentiality restrictions
9.33 The manner in which confidentiality is applied in international merchandise trade statistics can cause negative values to be displayed in some outputs. The following paragraphs describe why negative values exist and why they are important. The information is complex but is essential for users who purchase the complete international merchandise trade data set and do their own data extractions and manipulations. Users of publication tables, spreadsheets or data cubes and users who purchase specific commodities, countries or other components of the data will never see negative values.
9.34 During output processing, four different types of output record are created to protect confidential trade and ensure the maximum release of data. The four types of record are:
- records providing information on trade not subject to confidentiality restrictions (type i)
- records enabling the release of the greatest possible level of information on commodities subject to confidentiality restrictions (type ii)
- records enabling the release of the greatest possible level of information on trade with countries, relating to Australian states, or passing through overseas or Australian ports, where confidentiality restrictions apply to these items (type iii)
- records derived from record types ii and iii above, which serve as balancing items, so that totals can be easily and accurately calculated for items which are subject to confidentiality restrictions (type iv). These records have negative values.
9.35 For records involving commodities not subject to confidentiality restrictions, only one output record is created (type i). This record is identical to the aggregates of records prior to the application of confidentiality.
9.36 For records involving commodities which are subject to confidentiality restrictions, two different output records (types ii and iii) are created, to replace a single input record. In this way only the confidential data are suppressed.
9.37 Replacing a single input record with two output records means that, if no further action were taken, there would be some double counting in reports which list trade in all commodities with all countries. The type iv record overcomes this problem by offsetting the double counting that would otherwise occur.
9.38 To illustrate by an example, with a 'No Country Details' restriction, only the country (and port) data should be concealed. By creating a type ii record, the value, quantity and commodity details are preserved for output that does not include country or port information. By creating a type iii record, country and port details are preserved for output that includes country and port information but commodity details are suppressed. The value and quantity are included in 'Combined confidential items'. The type iv record is created to avoid double counting in totals.
9.39 The above was true for all commodity codes with confidentiality restrictions prior to the changes introduced in September 2008 for imports and June 2013 for exports. From the above dates, the offsets described above are true for commodity codes with a 'No Country Details' restriction, 'Selected Country Details' restriction, 'No State Details' restriction and 'Selected State Details' restriction. However for commodity codes with a 'No Commodity Details' restriction, only the type ii record is created. This means the offset record that overcomes double counting is not needed to protect confidentiality as only one output record is created.
Aggregations of data
9.40 Data that are subject to confidentiality restrictions can sometimes be provided on a more aggregated basis as a special data report. Where a commodity code has been confidentialised, it may be possible to release information aggregated over a longer time period (for example quarterly, six-monthly or annually) with a reduced confidentiality restriction. This is known as time aggregation
9.41 Alternatively, information may be aggregated for selected commodity codes. Reports of this nature are checked to ensure that confidentiality is preserved. However, this greater level of aggregation can, in some cases, mean that more data are available.
9.42 Requests for the supply of data on an aggregation basis attract a fee to meet the cost of determining whether or not there is a level of aggregation which would enable release of otherwise confidential data. The fee is payable regardless of the outcome. Any request for aggregate data should be addressed to the International Trade in Goods and Services Section, Australian Bureau of Statistics: international.trade@abs.gov.au.
Further information
9.43 For more information on the application of confidentiality procedures and restrictions, refer to the Information Paper: International Merchandise Trade Statistics, Australia: Data Confidentiality 1999 (cat. no. 5487.0). A feature article on data confidentiality, in particular its impact on publication tables, was also included in the December quarter 1999 issue of International Merchandise Trade, Australia (cat. no. 5422.0).