Process modelling is widely used in business and science and is often used by companies for representing important business processes. The process is represented in a simplified, graphical way which can be used for documentation, communication and testing purposes.
The appearance of process models is a very important area of research, as it has an impact on the understandability of the process model. A lot of research is done in the area of process model understandability concerning influencing factors, the modelling language and visual features of a model. However, the layout of a process model and its influence on the understandability of a process model still needs further research. In particular, it is unclear whether certain layout properties do have a significant impact on the understandability of a process model.
This thesis takes a look at two layout properties: the change of direction and the visibility of blocks. It investigates whether these properties have an impact on the understandability of process models.
To get empirical data on the actual impact of these properties on the understandability of the process models, a controlled experiment was conducted. In this experiment 68 students from the University of Ulm participated.
While the change of direction does not have a significant effect on the response variables accuracy and duration in general, it has a significant effect on the response variable duration for global question types. The visibility of blocks feature has a significant impact on the duration in general and additionally has a significant impact on the accuracy for global question types. These results should be able to help improving automated layout algorithms and guidelines for the process model creation, as well as the training of future process modellers.