Visual strategies for enhancing user perception of task relationships in emergency operations centers

In time-sensitive environments, such as DHS emergency operations centers (EOCs), it is imperative for decision makers to rapidly understand and address key logical relationships that exist between tasks, entities, and events, even as conditions fluctuate. These relationships often have important temporal characteristics, such as tasks that must be completed before others can be started (e.g., buses must be transported to an area before an evacuation process can begin). Unfortunately, traditional temporal display methods, such as mission timelines, typically reveal only rudimentary event details and fail to support user understanding of and reasoning about critical temporal constraints and interrelationships across multiple mission components. To address these shortcomings, we developed a visual language to enhance temporal data displays by explicitly and intuitively conveying these constraints and relationships to decision makers. In this paper, we detail these design strategies and describe ongoing evaluation efforts to assess their usability and effectiveness to support decision-making tasks in complex, time-sensitive environments. We present a case study in which we applied our visual enhancements to a timeline display, improving the perception of logical relationships among events in a Master Scenario Event List (MSEL). These methods reduce the cognitive workload of decision makers and improve the efficacy of identification.