1. Broad description
After the initial success of releasing licensed microdata files (anonymised and protected against disclosure) from its social sample surveys from 1994 onwards, researchers also developed a demand for accessing other microdata files: business survey microdata, fiscal income data, cause-of-death data, and the like. Such data are much less easy to protect against disclosure because important variables are very skewed in their distributions, samples are much more stratified and even integral in some (or all) strata, and so on. The solution to serve the needs of these researchers was to create a separate research facility, a data laboratory, within the safe walls of Statistics Netherlands' (Central Bureau voor de Statistiek, or CBS) two establishments, with most universities within an hour's reach. So with this solution the microdata does not go to the researcher but the researcher comes to the microdata. In 1998 the Centre for Research on Economic Microdata (Cerem) was established after fairly long consultations with business representatives who needed to be convinced of the utility and the safety of academic on-site analysis of business microdata. Subsequently on-site facilities were also used by researchers on social microdata with more detail than can be found in the licensed microdata files, and by researchers on social microdata from matched administrative data.
More recently the Centre for Policy related Statistics (CPS) was set up as a department of Statistics Netherlands in 2002 in response to an increasing demand for statistical information by government policymakers and national planning agencies. One important factor in this respect was the demand for statistics to measure the effects of policy measures, and to gain insight into possible effects of a change in policy measures.
These demands are mostly of a short-term character. Almost inevitably the statistical programme of a national statistical agency like Statistics Netherlands (SN) is not suited for short-term changes. Instead the programme is based on producing statistics that can be compared over time and therefore have a slow rate of change. This makes it difficult to fulfil the needs of government departments and planning offices in this respect.
The CPS was set up to improve the fulfilment of these demands. Flexibility was achieved by making the working programme of the Centre dependent on the demands of the departments and planning offices. Only a few of the staff are paid directly from the budget of SN. Other demands for statistics are paid directly by the departments. A pilot project was set up with the Ministry of Social Affairs and Employment in 2002. This pilot was successful and led to a further increase in services.
2. Why is it good practice?
The data laboratory arrangement makes it possible to have microdata analysed in a safe setting. The microdata themselves cannot always be protected; for example, the producer of light bulbs from Eindhoven will always be recognisable and indispensable at the same time. But the settings in which these microdata are analysed are fully controlled. The number of days spent in the data laboratories is increasing each year by more than 20% and has now surpassed 1500.
3. Target audience
Microdata are made accessible under a contract or license to legitimate researchers only. Section 41 of the law cites the researchers that are qualified. These include the universities and other research institutes with a legal foundation, but also Eurostat and the EU NSOs. A residual category of applicants must be formally admitted by the Central Commission for Statistics (CCS), the supervisory body for CBS. The CCS has set its own criteria and procedures for deciding, in which a focus on statistical (aggregate) research, independence from administrative authorities, and the intention to share results in the public domain are predominant. The CCS has no principal objection against admitting non-EU universities, for example, but a commercial bank or a journalist would not be eligible. In practice, researchers seem to have better methodological qualifications when working on site, if only because their microdata and statistical models and software are complex in comparison with the social analysis of official social sample survey microdata at the universities. At present only researchers affiliated with Dutch research institutes are allowed.
4. Detailed description
The services of CPS can be divided into three groups.
- First there is the advisory function. The Centre can give advice about the possibilities of doing research on a specific question. Because the CPS staff have a broad knowledge of the available data sources, this can help to reduce data collection costs.
- Secondly, as mentioned above, CPS can itself conduct research on request. This research is done solely on existing data material; no additional survey activity is undertaken in this respect.
- A third activity is the possibility to provide access to microdata for researchers from outside SN. The microdata are made available at the level of individual records where, of course, direct identifiers are removed.
The datasets are all well documented, making it possible for researchers to gain access to the material efficiently and to evaluate the relevance of the dataset for their research.
Furthermore, precautions are taken to ensure that the security of the process is maximised.
Most microdata are made available for analysis on-site: i.e. researchers work at one of the offices of Statistics Netherlands on a dedicated infrastructure. For reasons of security, this infrastructure is physically disconnected from Statistics Netherlands' production environment and visitors only have access to the micro datasets they need for their specific research.
A second type of microdata service is remote execution. Using this service, researchers may send in scripts to be executed on well-defined sets of micro data.
For all types of microdata services, checks on the possibility of statistical disclosure are performed before results are made available to researchers for use outside the secure environment.
From mid-2005 a remote access facility has been developed, making it possible for researchers to analyse microdata present at SN through a secure connection from workstations in their own institute. This facility is much like the facility in use in Denmark.
Part of the security regime here is the use of a secure Internet connexion and the application of biometric identification (fingerprints) and PKI certificates.
The on-site facilities for microdata analysis within SN developed in recent years originate from different departments, and were designed slightly differently. Apart from the on-site facility within the CPS, there were separate facilities within the department for social statistics and a facility for economic statistics, known as CEREM (Centre for Research on Economic Microdata). At the end of 2005 all the activities for microdata services were pooled within the CPS, enabling a more transparent and more efficient microdata access. This means that, although CEREM as such is no longer in existence, CPS offers the same facilities and availability for microdata analyses.
The use of microdata is expected to grow rapidly the coming years. In this respect, the remote access facilities in particular are promising.
5. Supporting legislation
In 2003 the statistical legislation allowing the release of microdata was rephrased to make formally possible the analysis of microdata on site in a data laboratory. Section 41 now makes it possible "to provide or grant access to a set of data".
The main strength from the perspective of the researcher is that there is hardly a limit to the amount and nature of microdata that can be analysed.
The main remaining weakness, at least from an international perspective, is the language used for documentation. Plans for making the documentation in English are foreseen for the coming years.
The Centre for Policy related Statistics can be reached by e-mail at CvB@CBS.nl. Within the CPS, contact persons are Frans Hoeve (+31 70 337 5609 of FHVE@CBS.nl) and Gerhard Meinen (+31 70 337 4228 or GMNE@CBS.nl).
30 Aug 2013