It is not always necessary to collect your own data for research. A range of high-quality data sources is already available through public databases, statistical institutions, research infrastructures, and thematic repositories. Reusing existing data can save time and costs, enable comparisons of results across studies, and in some cases provide access to larger or longer-term datasets than would be possible to obtain through primary data collection. When selecting data, however, it is important to assess their origin, quality, documentation, conditions of use, and suitability for the specific research question.
Below you will find an overview of selected sources that may be useful when searching for and reusing existing research data.