Presenting health risk information in different formats: the effect on participants' cognitive and emotional evaluation and decisions.

OBJECTIVE: Effective communication of health risks plays an important role in enabling patients to make adequate decisions. There is little--though contradictory--evidence to indicate which format is most effective for communicating risks, and which risk format is preferred by counselees.
METHODS: In an experiment, subjects were presented health scenarios and risk information in different formats (percentages, frequencies, and population figures) and asked to evaluate the risks and make a decision based on these.
RESULTS: Different risk formats had different effects on respondents' evaluation of the health risks presented. Contrary to our expectation, population figures were not evaluated as being the easiest format for all decision problems. Population figures were shown to have the biggest affective impact, and risks presented as population figures were also evaluated as significantly greater than the risks presented in other formats. The format of the presented risks influenced their decision in only one out of four decision-making situations, although in a second situation there was a similar trend.
CONCLUSION: This study suggests that the risk format plays a role in the decision-making process, although it remains unclear which format is the most effective in terms of understanding. PRACTICE IMPLICATIONS: More experimental studies based on a theoretical analysis of the factors that promote effective risk communication are needed in the general population as well as in clinical settings with patients actually experiencing the risks and making the decisions.