Maintaining credibility when communicating uncertainty: the role of directionality

Abstract Risk communicators often need to communicate probabilistic predictions. On occasion, an event with 10% likelihood will occur, or one with 90% likelihood will not – a probabilistically unexpected outcome. Previous research manipulating communication format has found that communicators lose more credibility and are perceived as less correct if an “unlikely” event occurs than if a “10–30% likelihood” event occurs. We suggest “directionality–outcome congruence” underlies the perception of predictions as “erroneous”. For example, the negatively directional term “unlikely” led to harsher ratings because the outcome was counter to the original focus of the prediction (on the event’s non-occurrence). In the context of both probabilistically unexpected (Experiment 1) and expected (Experiment 2) outcomes, we find that communicators are perceived as less credible and less correct given “directionality–outcome incongruence”. Communicators should thus carefully consider the directionality implicit in their risk communications to maximise communication effectiveness.