Knowledge is receiving recognition as a strategic force in organizations. Correspondingly, one form of knowledge capture and maintenance organizations are tempted to use is expert system design by end users. The article discusses difficulties associated with end user development, both in terms of design quality and knowledge content. An analysis of 25 expert systems written by non-professional developers reveals significant quality and size limitations that indicate limited feasibility of end user expert system development. Furthermore, the lack of design quality may not be easily compensated for by a “knowledge advantage” of the end users, as end users may have a performance advantage in using their knowledge, but not in “knowing” it.