Color and Uncertainty: It is not always Black and White

To fully comprehend the meaning and impact of visualized data it is crucial that users are able to perceive and comprehend the inherent uncertainty of the data in a correct and intuitive way. Data uncertainty is frequently visualized through color mappings. Previous studies argued that color hue is not suitable for communicating uncertainty because most hue scales lack an intrinsic perceptual order. In this paper we examine the use of hue for communicating data uncertainty in more detail. We investigated the potential of distinct color triples (rather than the entire spectrum of colors, as used in previously studies) to represent different levels of uncertainty. We identified several color triples that reliably map to an intuitive ordering of certainty. Bipolar color scales constructed from these color triples can be used to communicate uncertainty in visualizations, particularly to audiences of nonspecialists. A ‘traffic light’ configuration (with red and green at the endpoints and either yellow or orange in the middle) communicates uncertainty most intuitively.