Microdata Policy & Procedure : File use Categories, Data Anonymization for Personal Data Protection and Confidentiality
The National Bureau of Statistics and other data producers are increasingly publishing macro and microdata obtained from sample surveys, censuses, and administrative data collection systems. The dissemination of microdata is made necessary by a high demand from the research community, a push for transparency, and sometimes by legal or contractual obligations. This was done in such a way that the confidentiality of the information provided by respondents is preserved.
NBS therefore adopt the international standards of releasing microdata in accordance with the International best practices in protecting personal data and confidentiality of data suppliers.
In accordance with the personal data protection policy, The confidentiality of the individual respondent to NBS data supply is protected by law (Statistical Act 2007). This is published in the Official Gazette of the Federal republic of Nigeria No. 60 vol. 94 of 11th June 2007. Section 26 "Confidentiality and Disclosure" and Section 27 "Dissemination and Access" on Statistics Act 2007 is very clear about only releasing data that are fully anonymized to the public.
Anonymizing a micro dataset is about removing or modifying identifying variables before dissemination. That is, all identifying variable that anyone can use to describes a characteristic of a person that is observable, that is registered (identification numbers, etc.), or generally, that can be known to other persons is removed before publishing the data.
Below are the content of Statistics Act 2007 about Confidentiality and Disclosure as well as Data Dissemination.
(1) The provisions of this Act shall not affect any law relating to the disclosure or non-disclosure of any official secret or confidential information or trade secret
(2) Data collected for statistical purposes shall be treated as confidential and Data confidentiality means that the dissemination of these data (and the statistics which can be calculated from them) shall not permit the identification directly or indirectly of the units concerned and that a prohibition is imposed on data producers against disclosing information of an individual nature obtained in the course of their work.
(3) Except for the purpose of prosecution undertaken by the Bureau.
(a) no individual return or part thereof, made for the purposes of this part of this Act;
(b) no answer given to any question for the purposes of this part of this Act;
(c) no report, abstract or other document, containing particulars comprised in an); return or answer so arranged as to enable such particulars to be identified with any person, undertaking or business, shall be published, admitted in evidence or shown to a person not employed in the execution of a duty under this Act without the prior consent in writing of the person making the return or giving the answer, or in the case of an undertaking or business of the person who for the time being is the owner manager or controller of the undertaking or business.
(4) Notwithstanding the provisions of subsection (1) of this section, a report as abstract or other document may be published without the required consent if
(a) the information about an enterprise or establishment is already published or available on a database accessible to the public at large.
(b) in the case of a monopoly or duopoly, the statistics of relevant sectors of activity are none the less open and publishable, provided they do not reveal costs of production or profits of individual enterprises.
(5) Nothing in this part of the Act shall be constructed as.
(a) authorizing or requiring the disclosure or production of any information or document if the disclosure or production of the information of document would contravene the provisions of any law for the time being in force;
(b) prohibiting or restricting the disclosure or production of any information or document which is authorized or required to be disclosed or produced under the provisions of any law for the time being in force.
(6) A person required under the provision of this part of this Act to furnish any information, estimate, return or particular shall not be obliged to disclose an information or produce a document which—
(a) he would not be compellable to disclose or produce if he were a witness in a court of law; or
(b) would involve the disclosure of any trade to require the disclosure to Ministry Department or Authority for the purpose of taxation of any information acquired under the provisions of this Act.
(1) Data producers shall be required to process, disseminate and make accessible to users as a "public good" data collected or compiled using public funds.
(2) Data producers will be required to release micro level data sets for further analysis, with suitable proviso on confidentially, unless there is a compelling reason, such as maintaining confidentially, not to do so.
(3) Each year the Board will publish in advance the data to be produced together with date for the release of the data and all data producing agencies including the Bureau will be required to have a data release policy. To be made publicly available and they have power to impose charges for data products and services.
Micro-datasets are categorized into three groups, according to the sensitivity of their content and their inherent disclosure risks:
Public use files
Public use files are microdata files characterized by a low disclosure risk, or by the fact that respondents gave their formal consent to the data dissemination. They are made available on-line to all interested users, for research and statistical purposes only. Users are asked to complete an on-line form and agree to abide by our terms and conditions before being provided with the data.
This approach involves a signed agreement between the National Data Archive and external trusted users, to permit them to access semi-anonymized data files. Licensing agreements are only entered into with bona fide users when there is an appropriate sponsoring institution or referee. Users must be able to:
Those interested in accessing the data under license should fill our Licensed Dataset Request Form. Requests are evaluated by a our Microdata Release Panel. When the decision is made to grant access to the data, users will receive them through secure ftp server.
Files accessible on-site (data enclave)
Where the data is particularly sensitive, access is only provided on-site in our data enclave under strict conditions, and only for research purposes. The data enclave is located in [location: agency, city, country]. The computers within the enclave are not linked to the outside world; researchers do not have email or internet access.
Permission to access the data enclave must be submitted using our Enclave Access Request Form (which provides detailed information on conditions and rules of access). Authorized users are required to sign a formal Microdata Access Agreement. Further, the National Data Archive will scrutinise the generated outputs in a full disclosure review before they are released.