The failure of a delivered information system (IS) to match users' expectations of it is a frequent cause of project failure. This paper examines some of the causes of expectation failure, in particular the development of inappropriate mental models of a new IS by users. The documents traditionally used to express the requirements for a new IS are seldom fully understood by users, and often prove hard to verify. Documents written for, with, and sometimes by the users-the user manuals-have proved more successful in these respects.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

In a companion paper (1994) I argued that the mismatch of a delivered Information System (IS) to the users' expectations of it is a frequent cause of project failure. These expectations are held in a conceptual structure, referred to by some authors as a mental model. Helping users develop appropriate mental models of the new IS in an early project phase is an important element in managing expectations, but the documents traditionally used to express and check users' requirements often fail in this regard. Over the last two decades a few authors have found that user manuals written early in the project can be very effective as a means of communication between developers and users. This paper reviews the literature and describes the different roles that user manuals can play throughout a project. It provides practical advice for professional communicators, project managers, and other project personnel.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>