Elfie Swerts and Georg Lutz / Guest Authors

Foto: istock.com/Orbon_Alija

Data linkage, i.e. the aggregation of data from different sources relating to the same entity or individual, provides major advantages for research and is a key factor when it comes to obtaining greater knowledge in the fields of medicine and society in Switzerland. However, major challenges arise in connection with the linking of data, the access to and archiving of linked data with regard to data documentation, data access and linking procedures and, most importantly, data protection. The linkhub.ch initiative aims to promote the creation of a comprehensive legal and institutional framework that will make data available and linkable for research purposes while ensuring that the privacy of individuals is protected and that academic principles are respected.

German version

The proliferation of data and the multiplication of data sources as a result of the digital revolution offer unprecedented opportunities to generate knowledge about societies. The provision of access to high quality data for analytical purposes is a key factor if research by governments, academic institutions and the private sector is an important strategic resource that will enable Switzerland to conduct cutting-edge research at the international level and to inform national policies in the best possible way.

The extent to which policymaking depends on access to good data has recently been made apparent. The current coronavirus crisis has strikingly demonstrated the acute necessity of obtaining data from the public and private sectors so that many of the aspects of the current situation can be monitored and analysed. It has also made manifest the shortcomings of the current legal and institutional frameworks when it comes to making use of this data.

Data linkage offers even greater analytical potential

Linking of data is linking is the aggregation of data from different sources related to the same entity or individual. This makes it possible to acquire new information from existing data while the accumulation of large volumes of data augments their value: a single data collection often provides limited insights while the combination of different sources can represent a rich reservoir of information. For example, a death register by itself has restricted analytical potential. However, if a death register can be combined with information about individuals, it can be used to investigate a large number of relevant research questions, such as the social and health factors that influence life expectancy.

  • Linking of data thus provides major advantages for research, particularly in the medical and social sciences:
  • It increases the accuracy and richness of the data, enabling research that would otherwise be impossible.
  • It improves cost-effectiveness: it can be very expensive to design a way to collect specific data while the use of existing data can reduce costs.
  • It reduces the burden on survey respondents: data need not be collected directly from individuals or businesses.

The challenges of linking data

However, while it is undisputed that high quality data is of considerable value, linking of data and the access to and archiving of linked data face many challenges.

  • Administrative and private data are far from being FAIR (findable, accessible, interoperable and reproducible) for researchers.
  • Complete metadata sets and documentation either do not exist or are not publicly available.
  • Access is complicated or denied, and if the data is accessible, data use and linkage can only occur within a very limited framework or not at all.
  • Researchers often have to delete their data, which runs counter to the principle that demands that scientific results be reproducible.

Even more importantly, data linkage comes with greatly increased concerns with regard to privacy: if there is more information available about a person, this can make it easier to identify them. The information can be sensitive, which can further increase the risk of potential harm from the disclosure of personal data.

The linkhub.ch initiative

In order to support academic and administrative projects that employ linked data while at the same time providing for the protection of personal information, various institutions and research groups (see the infobox) have launched a joint political initiative: linkhub.ch.

The Swiss Academy of Humanities and Social Sciences SAGW and the Swiss Academies have commissioned linkhub.ch to produce a report. This report will provide a basis for the development of a research-friendly institutional framework, allowing more comprehensive access to data for research and facilitating the linking of data, while respecting the rights of individuals to privacy and data protection.

In this report, the requirements of and challenges facing researchers who need to access administrative and private data as well as the legal framework that governs the access to and linking of administrative and private data for research purposes are analysed. Solutions that will facilitate access to administrative and private data are also proposed. This report is intended for the competent bodies in the fields of education, research and innovation (SERI, FNS, swissuniversities, Swiss Academies) and other stakeholders.

linkhub.ch proposals

Concrete solutions are proposed that are designed to meet both the needs of researchers to access and link data, and the need to reinforce data protection. One possible approach would be to enhance access to information and improve data documentation, ensuring that there is an awareness that the required data exists and it can also be readily found. Other proposed solutions aim to address security issues relating to data matching by using certain procedures that can be put in place to link data; these are based on two key principles:

  • The one requires the separation of variables containing information that identifies individuals (identifiers, name, date of birth, etc.) from other variables.
    For the process of linking, only the identifying information will be required but not the other variables: from the identifying information, a linking key (a code assigned to the same individual in different data sources, allowing identical individuals in the different data sources to be linked) can be generated. Subsequently it will be possible to merge data from different sources using the linking key without the need to use any identification information.
  • Differentiated forms of access based on data sensitivity: on-site access only for highly sensitive data, secure remote access for sensitive data and download access for less sensitive data.

These proposals are complemented by suggested changes to the legislative framework, working on the assumption that equitable access to personal data must be subject to and regulated by the data protection rights of individuals.


The need to protect the privacy of individuals in a digitised world is being increasingly recognised as being as important as the knowledge gained through data analysis. The need to protect privacy should therefore not preclude the use of personal data for research, but should underlie the creation of a comprehensive legal and institutional framework that makes data available for research while ensuring that the privacy of individuals is protected. This is the aim of the linkhub.ch initiative.

Linkhub.ch is a political initiative the objective of which is to promote the creation of a legal and institutional environment that supports the use of linked data for academic and administrative research while at the same time respecting the need to uphold personal data protection and academic principles. The partners of the linkhub.ch project are:
– FORS – Swiss Centre of Expertise in the Social Sciences
– TREE – Transitions from Education to Employment
– NCCR on the move – National Center of Competence in Research for migration and mobility studies.
– SwissRDL – Medical Registries and Data Linkage
– The Swiss Network on Fiscal Federalism


Articles and reports:

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