The Physics of Notations: Improving the Usability and Communicability of Visual Notations in Requirements Engineering

Abstract

isual notations form an integral part of the language of requirements engineering (RE), and have dominated RE research and practice from its earliest beginnings. An RE method without a visual representation is almost unheard-of. The primary reason for using visual notations is to exploit the power of human visual processing and thereby optimise human communication and problem solving. Visual representations play a particularly critical role in communicating with end users and customers, as diagrams are believed to convey information more effectively to non-technical people than text. Surprisingly, RE researchers and notation designers have ignored or undervalued issues of visual representation. In evaluating and comparing notations, details of visual syntax are rarely discussed. In designing notations, the majority of effort is spent on semantics, with graphical conventions largely an afterthought. Decisions about graphical representation tend to be made in a subjective way, without reference to theory or empirical evidence, or justifications of any kind (design rationale). Finally, while RE has developed mature methods for evaluating and designing semantics of notations, it lacks equivalent methods for visual syntax.