Research into risk communication has commonly highlighted
the disparity between the meaning intended by the
communicator and what is understood by the recipient. Such
miscommunications will have implications for perceived trust
and expertise of the communicator, but it is not known whether
this differs according to the communication format. We
examined the effect of using verbal, numerical and mixed
communication formats on perceptions of credibility and
correctness, as well as whether they influenced a decision to
evacuate, both before and after an ‘erroneous’ prediction (i.e.
an ‘unlikely’ event occurs, or a ‘likely’ event does not occur).
We observed no effect of communication format on any of the
measures pre-outcome, but found the numerical format was
perceived as less incorrect, as well as more credible than the
other formats after an ‘erroneous’ prediction, but only when
low probability expressions were used. Our findings suggest
numbers should be used in consequential risk communications
