Electronically Stored Information or ESI is information that is stored electronically on enumerable types of media regardless of the original format in which it was created.
Electronically Stored Information: this is an all inclusive term referring to conventional electronic documents (e.g. spreadsheets and word processing documents) and in addition the contents of databases, mobile phone messages, digital recordings (e.g. of voicemail) and transcripts of instant messages. All of this material needs to be considered for disclosure. 1
Used in Federal Rule of Civil Procedure 34(a)(1)(A) to refer to discoverable information “stored in any medium from which the information can be obtained either directly or, if necessary, after translation by the responding party into a reasonably usable form.” Although Rule 34(a)(1)(A) references “Documents or Electronically Stored Information,” individual units of review and production are commonly referred to as Documents, regardless of the medium. 2