Using Search to Improve Visual Understanding and Appreciation of Process Model Diagrams

Abstract: This thesis focuses on comparing four different layouts of the same process model diagram in terms of user understanding and appreciation. When the model diagram is aligned around the shortest path from start to goal, it represents the version of a process where everything goes as planned. By comparing the shortes t path layout to other layouts (versions of the process), the aim was to investigate if users found it easier to understand and more visually appealing. The layouts compared were an artistic layout, where the nodes and edges were placed in anequidistant and harmonious structure. Secondly, a max length horizontallay out that aligned the process model’s flow of information to follow the longest path from start to goal. Lastly, a base line layout where the nodes and edges were drawn more at random without following any particular structure. By comparing qualitative data from users to measure their appreciation, as well as quantitative data from their response time and accuracy, the primary goal was to see if the min length shortest path layout would increase the user’s understanding and appreciation, compared to the baseline layout. To realign the base layout into a shortest path layout, an implementation of the A' search algorithm with Euclidean distance heuristics was used. A user study with 35 participants showed a statistically significant difference in performance between the layout modified by the algorithm, and the base line layout. User response time and accuracy improved by more than what can be explained by random chance, suggesting that the implementation can be used for said purpose. The max length layout performed even better, and the best performing layout was the artistic.