- An accepted assumption underlying application development is that the user is naive, with little understanding of data processing. All the methods for handling the information system development process, from structured analysis to prototyping, have in common a concern with user/developer communication, yet always under the assumption that users are alike in their capacity to understand data processing.This paper proposes to examine this preconception of the user. With the prevalence of end-user computing, users should no longer be considered universally ignorant of information systems. Moreover, sophisticated information center veterans, as well as microcomputer users, can and do contribute to system development. They are capable of preliminary experimentation with system requirements, in particular those related to user interface. Thus, the concept of end-user prototyping is developed and demonstrated, presenting information systems professionals with an opportunity to profit from enhanced user sophistication.