Intelligent technologies used to search for relevant documents in electronic discovery during data processing or review. Concept search technology differs from basic keyword search because concept searching can identify electronically stored information (ESI) (including paper documents that have been scanned and converted to ESI) that is related to the term or phrase included in a search, whether or not the specific term or phrase is contained in the ESI. For example, if a search contains the term "taxi," the concept search might also include in its results documents containing the term "cab."

Concept search technologies vary in terms of the breadth of documents they find responsive to a search. Some programs search for synonyms and word variations, while others can search for more advanced themes and categories. Whatever method of concept searching is employed, counsel should understand and document the parameters of their searches.