User Evaluation of Symbols for Core Business Process Modeling Concepts

Process modeling notations are visual languages that use symbols to represent their main concepts. This study investigates the quality of such symbols from users’ perspective. The design of a symbol influences whether it is easy to spot in a model and is correctly associated with the concept it represents. In an empirical study with 188 participants, the normative ratings of process model symbols (for the basic concepts of start, end, task, AND, XOR) were gathered on the dimensions of perceptual popout, semantic transparency, perceptual discriminability, and aesthetics. Overall, the results are consistent with our predictions based on the theoretical analyses of the designs of the symbols. Prior familiarity with process modeling notations led to more clear-cut evaluations of routing symbols (AND, XOR) and a reduced tendency to prefer middle rating options, but it did not affect the evaluations of the other symbols. Standardization organizations and academic developers of notations can use insights from the study to enhance the usability of process modeling notations.