Making sense of uncertainty: advantages and disadvantages of providing an evaluative structure

In many decision contexts, there is uncertainty in the assessed probabilities and expected consequences of different actions. The fundamental goal for information providers is to present uncertainty in a way that is not overly complicated, yet sufficiently detailed to prompt decision-makers to think about the implications of this uncertainty for the decision at hand. In two experiments, we assess the pros and cons of providing an evaluative structure to facilitate the comprehension and use of uncertainty information and explore whether people who vary in numeracy perceive and use uncertainty in different ways. Participants were presented with scenarios and summary tables describing the anticipated consequences of different environmental-management actions. Our results suggest that different uncertainty formats may lead people to think in particular ways. Laypeople had an easier time understanding the general concept of uncertainty when an evaluative label was presented (e.g. uncertainty is High or Low). However, when asked about a specific possible outcome for an attribute, participants performed better when presented with numerical ranges. Our results also suggest that there appear to be advantages to using evaluative labels, in that they can highlight aspects of uncertainty information that may otherwise be overlooked in more complex numerical displays. However, the salience of evaluative labels appeared to cause some participants to put undue weight on this information, which resulted in value-inconsistent choices. The simplicity and power of providing an evaluative structure is a double-edged sword.