An Evaluation of Temporal and Categorical Uncertainty on Timelines: A Case Study in Human Activity Recall Visualizations

Encoding uncertainty in timelines can provide more precise and informative visualizations (e.g., visual representations of unsure times or locations in event planning timelines). To evaluate the effectiveness of different temporal and categorical uncertainty representations on timelines, we conducted a mixed-methods user study with 81 participants on uncertainty in activity recall timelines (ARTs). We find that participants’ accuracy is better when temporal uncertainty is encoded using transparency instead of dashing, and that a participant’s visual encoding preference does not always align with their performance (e.g., they performed better with a lesspreferred visual encoding technique). Additionally, qualitative findings show that existing biases of an individual alter their interpretation of ARTs. Acopyofourstudymaterials is available at https://osf.io/98p6m/.