International collaboration has become very common in the production of scientific knowledge (Coccia and Wang, 2016; Monastersky &

Openness may sound self-evident, but in fact it can mean different things, even within the Open Science community (Pasquetto, Sands & Borgman, 2015). To align understanding and to ensure common goals in the transition to Open Science, clear definitions are needed.

When looking for a suitable repository, the discipline(s) a repository caters to is one of the most important pieces of information. The re3data Metadata Schema reflects this priority by requiring the element subject for all indexed repositories. However, describing the disciplinary focus of research data repositories is not an easy task.

To keep track of where you are going, you need to check your compass from time to time. For this purpose, the re3data COREF project undertook a series of workshops in 2020 and have now come up with a new Conceptual Model for User Stories for the Registry of Research Data Repositories – re3data. We are grateful to welcome you along this journey and share our results with you.

Detailed descriptions of research data repositories are at the core of re3data. They increase a repository's visibility by enabling re3data users to find a suitable service for storing their data. Repository descriptions are based on the re3data Metadata Schema, which covers various aspects of research data repositories, including general scope, content, policies as well as compliance with technical and metadata standards.

re3data offers detailed descriptions of more than 2600 repositories. These descriptions are based on the re3data Metadata Schema and can be accessed via the re3data API. There are many conceivable use cases for re3data metadata. We set up a GitHub repository where we provide some examples for using the re3data API. The examples are implemented in R using Jupyter Notebooks.

Data quality as a research topic in re3data COREF Among other activities, re3data COREF is conducting multi-method empirical research into data quality and data quality assurance practices at data repositories. Based on qualitative content analysis of data journal guidelines and CoreTrustSeal self assessment documents, we developed a survey that was distributed among operators of repositories indexed in re3data.

The German version of this article has been published on the DINI AG-FIS and AG-E-Pub blog. As a global directory, re3data describes research data repositories from all scientific disciplines. It lists repositories that enable researchers, funding organizations, publishers and scientific institutions to permanently store research data and ensure access to datasets.

UPDATE: The revised version 3.1 of the re3data Metadata Schema was published in August 2021 and can be accessed via the re3data website. re3data currently describes more than 2600 research data repositories from all disciplines based on the re3data Metadata Schema. The current version 3.0 of the re3data Metadata Schema was released in 2015.