Anything that can be used for analysis can be considered “data(sets)”. Many national and international organisations provide access to large datasets free of charge: this is called Open Data.
Datasets may contain different kinds of data files, e.g. raw or edited/cleaned data, and macro or micro data. Raw data refers to the data as they are primarily collected, and includes all data, even the missed or mismatched pieces in the data file. Edited or cleaned data refers to data that have been tidied up for analysis and publication. Macro data and statistics are results based on micro data units and provide a general overview of the micro data. Although datasets can contain data of varying type or aggregation level, and there may be overlap between these definitions, each element can contain very important information.
When re-using research data, scientists must be familiar with the rules and regulations governing data copyright, intellectual property rights, and laws governing sensitive or personal information. SURF has compiled a report on the legal status of raw data including information on the types of consent required for the re-use of data. Your Privacy Champion can answer questions about the use of personal data. IXA can provide legal help with the re-use of data.
See also the ZonMw explanation of different kinds of property rights in the Netherlands (text available in Dutch only).
The number of datasets that are available grows rapidly. Datasets are made available in many formats, by many people or organizations. Some datasets are raw files and some are specifically organised and formatted as databases that require a licence or subscription to use them. The library of the Vrije Universiteit Amsterdam has collected links to some of the data repositories used and has licensed several databases.
If you need help finding & using free or licensed sources you can contact the Research Data Services Helpdesk. For students and personnel in the fields of economics, finance, or organisation science a separate LibGuide has been created to help them find and use/re-use data.
You can also start looking for data in these four places:
Data portals of (governmental) organisations. Organisations that regularly collect (statistical) data sometimes offer these data through their own portal. An example is Eurostat, which collects and disseminates statistics at the European level, by country and by theme. Some of these websites have been linked in the Finding data LibGuide.
Researchers from the Vrije Universiteit Amsterdam have also developed some databases containing data collected during research. See here for some examples: