How are non-numerical prognostic statements interpreted and are they subject to positive bias?

OBJECTIVES: Frank, clear communication with family members of terminally ill or incapacitated patients has important implications for well-being, satisfaction with care and sound decision-making. However, numerical prognostic statements, particularly more negative ones, have been found to be interpreted in a positively biased manner. Less precise non-numerical statements, preferred by physicians, and particularly statements using threatening terms (dying vs surviving) may be even more subject to such biases.

METHODS: Participants (N=200) read non-numerical prognostic statements framed in terms of dying or surviving and indicated their interpretation of likelihood of survival.

RESULTS: Even the most extreme statements were not interpreted to indicate 100% likelihood of surviving or dying, (eg, they will definitely survive, 92.77%). The poorness of prognoses was associated with more optimistically biased interpretations but this was not, however, affected by the wording of the prognoses in terms of dying versus surviving.

CONCLUSIONS: The findings illuminate the ways in which commonly used non-numeric language may be understood in numeric terms during prognostic discussions and provide further evidence of recipients' propensity for positive bias.