All technical communication serves a particular purpose—typically to communicate ideas and concepts to an audience, or instruct an audience in a particular task. Technical communication professionals use various techniques to understand the audience and, when possible, test content on the target audience. For example, if bank workers don't properly post deposits, a technical communicator would review existing instructional material (or lack thereof), interview bank workers to identify conceptual errors, interview subject matter experts to learn the correct procedures, author new material that instructs workers in the correct procedures, and test the new material on the bank workers.