When you start collecting the data for your research, it may be useful to see if there is any available relevant research data by others. This could help you better decide if there is any unnecessary duplicate data work that you may want to drop or review.
When searching for existing research data, it would be useful to know how and where they are typically made available. In some cases, published journal articles may come with accompanying supporting research data. In some others, the research data could be made available in subject specific data repositories. Research data repositories generally store and organise research data for easy searching and retrieving.
Other than the subject specific data repositories, there are also institutional data repositories which are maintained by universities or research institutions. There are also national data repositories which are established by government entities. Most of the data deposited in these data repositories are publicly available.
Here are some repositories that you can use to search for existing third-party research data:
Subject Specific Data Repositories
Many subject areas have an associated data repository that can be used by researchers to share their own data as well as to search for data from others.
Institutional Data Repositories
Such repositories are backed by institutions and they generally guarantee support. In most instances, different types of datasets can be stored together, regardless of discipline. Data could be linked to publications related to the data.
National Data Repositories
National data repositories are generally established to preserve and provide access to government data which cover various topics and subjects, including education, population, natural resources, health, finance, and etc. The data are collated, produced and made publicly available by different government entities. Members of the public can access these data repositories to search and reuse the public data.