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Trade confidentiality
International Merchandise Trade Statistics confidentiality policy


Maintaining the cooperation of data providers is crucial to the provision of high-quality official statistics. Keeping personal or sensitive business information confidential is essential to maintaining that cooperation. As a result, Statistics New Zealand's policy for the release of most statistics, as required by the Statistics Act 1975, is to prevent disclosure of information about individual persons or businesses.

For international merchandise trade statistics, the Statistics Act 1975 provides for less restrictive confidentiality rules than for other statistics. This is because:

  1. Individual overseas trade transactions are treated by the New Zealand Customs Service as 'official information' and are accessible under the provisions of the Official Information Act 1982. This is due to the New Zealand Customs Service entries, which are the source documents from which trade statistics are compiled, being used for a variety of other purposes relating to border surveillance and tariff administration.
  2. Trade statistics are a 'double-entry' transaction between countries, and comparisons can be made between one country's exports and another's imports. This limits the effectiveness of any attempts by one country to protect the confidentiality of international merchandise trade statistics. However, these comparisons can be problematic due to exchange rate and timing differences.
  3. The publication of trade statistics without prior checking for confidentiality is a long-established practice both in New Zealand and overseas.

Businesses engaged in international trade accept the reasons for trade data being an exception to the normal practices of statistical confidentiality. However, this acceptance has been conditional on Statistics New Zealand's taking measures to suppress published data when approached by firms concerned that publication of commercially sensitive information would damage their business.

This paper sets out Statistics New Zealand's policy for preventing disclosure of confidential information in published international trade statistics. The aim of the policy is to provide, on request, protection for commercially sensitive business data, while minimising the level of reduction in the usefulness of the published and publicly available data.

The confidentiality policy for the release of international merchandise trade statistics

Consistent with section 37 of the Statistics Act 1975, Statistics New Zealand will not disclose importers' or exporters' names, addresses, New Zealand Customs Service client codes, or any other identifiers, without their written permission to do so.

Detailed international trade statistics are published without prior checking for disclosure. If an exporter and/or importer requests suppression, aggregated data that identifies individual trade transactions, can, at the discretion of the Government Statistician, be suppressed in future publicly available tables.

Where such a request is received, Statistics New Zealand will verify the alleged identification risk. If Statistics New Zealand concludes that a risk of identification exists, either directly or by deduction, then we will amalgamate the relevant items with other trade transactions to prevent disclosure. These arrangements will be put in place for discrete periods up to a maximum of two years. If no identification risk is found, Statistics New Zealand will decline the request for suppression.

Statistics New Zealand will reconsider the suppression if any party approaches Statistics New Zealand with evidence that the suppressed information is publicly available, providing the evidence is confirmed.

Suppression of trade transactions by Statistics New Zealand will not provide total assurance of confidentiality, as the New Zealand Customs Service may choose to disclose details from the export and import entry documents which provide the source for overseas trade statistics.

How to register a request for the suppression of data

Requests for suppression of merchandise trade data must be made in writing by the exporter or importer, on their letterhead, and signed by a senior executive. The request must contain:

  • the New Zealand Customs Service client code(s) used to export or import
  • the 10-digit New Zealand Harmonised System Classification/tariff code(s) that require suppression
  • the activity they are involved in, ie importing or exporting
  • the length of the suppression required
  • the reason for the suppression request.

Requests should be sent to:

Manager – Overseas Trade
Overseas Trade Section
Statistics New Zealand
Private Bag 4741

For more information:
Telephone: 04 931 4600

How Statistics New Zealand processes the request for suppression

  1. Statistics New Zealand will conduct a suppression examination when requested by an exporter and/or importer using the New Zealand Customs Service client code and name as supplied. The onus is on the applicant to supply the correct information.
  2. Statistics New Zealand will not be responsible for inferring whether an importer or exporter has changed their New Zealand Customs Service client code or name. If this case applies, the importer or exporter must reapply for suppression, supplying the correct New Zealand Customs Service client code and name. The onus remains on the importer or exporter to make available the corrected information to Statistics New Zealand.
  3. Suppression will be applied to the activity the importer or exporter is involved in. For example, a 10-digit code is suppressed for exports only if the identification risk lies with exports data.
  4. Suppression will be applied to the entire HS 10-digit code. Suppression of exports to, or imports from, specific countries is not available.
  5. In verifying identification risks, Statistics New Zealand will examine the number and/or dominance of other exporters or importers of the requested suppressed commodity. This will be examined over a minimum 12-month period using final export or import data.
  6. Examination for identification risk will not take place before an export or import transaction.
  7. The length of the suppression is determined by the importer/exporter, based on their assessment of how long the data is commercially sensitive. Statistics New Zealand will not make any judgement or undertake any research on the validity of their assessment.
  8. The New Zealand Harmonised System Classification (NZHSC), which is derived from the Tariff of New Zealand, is the primary commodity classification used for categorising entries and publishing international trade statistics. The lowest level of commodity detail released will be at the 10-digit NZHSC level. Concession code data is not released.
  9. Requests for suppression will be actioned in time for the scheduled release of international merchandise trade statistics relating to the month when the request has been received wherever possible. If this is not possible, the requester will be informed and the request will be implemented before the scheduled release of international merchandise trade statistics relating to the following reference month.

How Statistics New Zealand applies the suppression

  1. The suppression periods currently available are:
    • three-month rolling suppression
    • a minimum 12-month non-rolling suppression with the lifting of the suppression once a year for data older than 12 months, and
    • minimum 24-month non-rolling suppression with the lifting of the suppression every year for data older than 24 months. For the 24-month option only, the importer/exporter will be contacted before the suppression is lifted to see if they want to continue with the suppression.
  2. Statistics New Zealand will suppress the data for the shortest period consistent with protecting the interests of the business concerned. The facility to suppress data for discrete periods up to 24 months is already in place as an interim amendment to the previous policy.
  3. Once a code has been granted confidentiality, the suppression is then applied to the reference month, as stated in the letter to the exporter or importer.
  4. All 10-digit NZHSC items that are confidential are combined in a 10-digit confidential code 9809.00.00.00 “Confidential items”, for the required period of suppression. Once this suppression period expires, these items are then assigned back to their correct NZHSC code(s) and chapter(s). Prior to April 2002, the confidential item code was 9709.00.0009. Should it be possible to indirectly calculate the content of some sensitive cells after this process, additional suppression of non-sensitive cells may be employed to protect sensitive cells.
  5. When the suppression facility has been put into place for the first time, data is suppressed not only for the reference month, but for the three months prior to the reference month as well, so that all new and updated data is suppressed. This is because, for a given release of a reference month, the first three months are provisional and the fourth month is made final.
  6. Statistics New Zealand will publicly notify all users of all suppressed NZHSC codes through its website:
  7. Statistics New Zealand will publicise the updated confidentiality policy for the release of international merchandise trade statistics. This includes, but is not limited to, making the policy available on the Statistics New Zealand website and via the New Zealand Customs Service publications.
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