Saket, BahadorSimonetto, PaoloKobourov, StephenN. Elmqvist and M. Hlawitschka and J. Kennedy2014-12-162014-12-162014978-3-905674-69-9https://doi.org/10.2312/eurovisshort.20141162Task taxonomies for graph and network visualization focus on tasks commonly encountered when analyzing graphconnectivity and topology. However, in many application fields such as the social sciences (social networks),biology (protein interaction models), software engineering (program call graphs), connectivity and topology informationis intertwined with grouping and clustering information. Several recent visualization techniques, suchas BubbleSets, LineSets and GMap, make explicit use of grouping and clustering, but evaluating such visualizationshas been difficult due to the lack of standardized group-level tasks. With this in mind, our goal is to define anew set of tasks that assess group-level comprehension. We propose several types of group-level tasks and provideseveral examples of each type. Finally, we characterize some of the proposed tasks using a multi-level typology ofabstract visualization tasks. We believe that adding group-level tasks to the task taxonomy for graph visualizationwould make the taxonomy more useful for recent graph visualization techniques. It would help evaluators defineand categorize new tasks, and it would help generalize individual results collected in controlled experiments.