Frequency or probability? A qualitative study of risk communication formats used in health care.

BACKGROUND The communication of probabilistic outcomes is an essential aspect of shared medical decision making. METHODS The authors conducted a qualitative study using focus groups to evaluate the response of women to various formats used in the communication of breast cancer risk. FINDINGS Graphic discrete frequency formats using highlighted human figures had greater salience than continuous probability formats using bar graphs. Potential biases in the estimation of risk magnitude were associated with the use of highlighted human figures versus bar graphs and the denominator size in graphics using highlighted human figures. The presentation of uncertainty associated with risk estimates caused some to loose trust in the information, whereas others were accepting of uncertainty in scientific data. CONCLUSION The qualitative studyidentified new constructs with regard to how patients process probabilistic information. Further research in the clinical setting is needed to provide a theoretical justification for the format used when presenting risk information to patients.