Federated search is a technology that allows the simultaneous search of multiple searchable resources. Also known as parallel search, metasearch, or broadcast search, federated searching aggregates multiple channels of information into a single searchable point. In libraries, Federated search technologies can blend e-journals, subscription databases, electronic print collections, other digital repositories, and the Internet. A benefit of federated searching is that it reduces the time it takes to search for information across a wide variety of resources, and usually displays results in a common format.
Federated search tools feed the user’s search terms into a set of databases, and often a library catalogue. The engine makes single query requests that are distributed to each separate data source. The databases and catalogue then return their results to the search tool. It compiles them and offers them to the user The search then aggregates the results received from the engines, sorts them according to predefined criteria (e.g. relevancy), and presents them to the user. Because federated search systems search multiple databases, compile and then order results, they tend to present results slower than some discovery systems.