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Published on: September 19, 2012
Measuring risk perceptions: what does the excessive use of 50% mean?
Wändi Bruine de Bruin1, Katherine G Carman2
1Departments of Social and Decision Sciences and of Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, Pennsylvania (WBB)
Summary
When estimating health risks, using 50% may indicate uncertainty, particularly for those with lower education and numeracy. Explicitly asking about uncertainty improves understanding of risk perception.
Area of Science:
- Health decision-making
- Risk perception psychology
Background:
- Accurate risk perception is crucial for informed health choices.
- Individuals often use 50% disproportionately when estimating probabilities.
Purpose of the Study:
- To investigate if the 50% probability response signifies not knowing the actual chances.
- To examine the role of education and numeracy in this phenomenon.
- To assess the utility of eliciting "don't know" responses.
Main Methods:
- 1020 participants estimated survival/mortality probabilities.
- Participants indicated if their estimate was "good" or if they "didn't know" the chances.
- Demographic, medical history, and numeracy data were collected.
Main Results:
- The 50% response was more frequently associated with "don't know" than other probability estimates.
- Low education and numeracy correlated with using 50%, mediated by expressing "don't know".
- Uncertainty-expressed risk estimates showed weaker correlations with health indicators.
Conclusions:
- The 50% probability response may signal uncertainty, especially in individuals with low numeracy and education.
- Risk probabilities stated as "don't know" are less reliable indicators of actual risk perception.
- Eliciting uncertainty can enhance health decision models and educational strategies.
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