(Re)use of existing data

Instead of acquiring new data, it might be more efficient to reuse existing data. This may be data collected by others but also data you collected previously. Reusing research data offers numerous benefits to both individual researchers and the broader scientific community. In general, reusing research data is a practice that benefits researchers by saving time and resources, reducing data redundancy, improving the rigor of research through validation and reproducibility, enabling comparative and interdisciplinary studies, and promoting a collaborative scientific culture and knowledge exchange. Reusing existing data can sometimes be more ethically sound than collecting new data, especially when dealing with sensitive topics or vulnerable populations. It reduces the need to subject participants to additional data collection processes.

There are several ways to find existing research data for reuse. Here are some methods and platforms you can explore:

• Online Data Repositories and Data Archives, e.g., 4TU.ResearchData, Zenodo, DANS
• Institutional Repositories: Many universities and research institutions maintain their own repositories where researchers can deposit and access data related to their fields of study.

• Discipline-Specific Repositories: Depending on your research field, there might be specialized repositories that cater to specific types of data. Go here or to Re3data and OpenAire for an overview of data repositories listed by discipline
• Government and Public Data Sources: Many government agencies and organizations provide publicly available data for research purposes, for example: Statistics Netherlands (CBS), the data portal of the Dutch Government, CentERdata - an institute that collects, analyses, and makes (panel) data available for scientific research, the data portal of the Organisation for Economic Co-operation and Development (OECD)
• Research Publications and Journals: Research papers and articles often include supplementary datasets. These datasets can be found in supplementary materials sections or data repositories associated with the journal
• Data Search Engines: Some search engines, such as Data Cite are specifically designed to help researchers find datasets
• Collaboration with Researchers: Collaborating with other researchers in your field might provide access to their datasets, or they could direct you to relevant resources
• Contacting Authors: If you come across a research paper with interesting data, you can reach out to the authors to inquire about the availability of the underlying datasets
• Conferences and Workshops: Attend conferences and workshops related to your research area, as researchers often share their datasets in these settings

Remember that while finding existing research data is valuable, it's crucial to ensure that the data is appropriately cited, used according to assigned license, and relevant to your research objectives. Always respect data usage policies and ethical considerations when reusing data.

If you want to make sure that the data acquired from a data archive or a repository adheres to quality standards, you may check:

• The repository’s policy and guidelines
• Any certification it holds, such as the CoreTrustSeal and ISO/DIN standards
• The use of persistent identifiers such as DOI’s, which ensure the findability of the data

If you are obtaining existing data, that are not publicly available, from an external organization (e.g. hospital), a data agreement needs to be put in place. The type of agreement depends on the nature of collaboration between the parties. If you plan on obtaining data this way, or an organization has shared a data agreement with you to complete, please contact your data steward.