The effect of order of presentation of verbal probability expressions on numerical estimates in a medical context

The communication of uncertainty in health: A scoping review

OBJECTIVE

To conduct a scoping review of existing studies that examine communication strategies that address uncertainty in health and categorize them using the taxonomy of uncertainty.

METHODS

Relevant articles retrieved from ten databases were categorized according to the dimensions of the taxonomy of uncertainty, and study characteristics were extracted from each article.

RESULTS

All articles (n = 63) explored uncertainty in the context of probabilistic risk and related to scientific issues (n = 63; 100%). The majority focused on complexity (n = 24; 38.1%) and uncertainty experienced by patients (n = 52; 82.5%). Most utilized quantitative methods (n = 46; 73.0%), hypothetical scenarios (n = 49; 77.8%), and focused on cancer (n = 20; 31.7%). Theory guided messages and study design in fewer than half (n = 27; 42.9%).

CONCLUSIONS

Heterogeneity in terminology used to refer to different types of uncertainties preclude a unified research agenda on uncertainty communication. Research predominately focuses on probability as the source of uncertainty, uncertainties related to scientific issues, and uncertainty experienced by patients.

PRACTICE IMPLICATIONS

Additional efforts are needed to understand providers' experience of uncertainty, and to identify strategies to address ambiguity. Future studies should use consistent terminology to allow for coherence and advancement of uncertainty communication scholarship. Continued efforts to refine the existing taxonomy should be undertaken.

Do people understand IARC's 2B categorization of RF fields from cell phones?

In May 2011, the International Agency on Cancer in Research (IARC) issued an official statement concluding that cell phone usage was "possibly carcinogenic to humans." There have been considerable doubts that non-experts and experts alike fully understood what IARC's categorization actually meant, as "possibly carcinogenic" can be interpreted in many ways. The present study is based on an online survey indicating that both the characterization of the probability of carcinogenicity, as well as the description of the risk increase given in the IARC press release, was mostly misunderstood by study participants. Respondents also greatly overestimated the magnitude of the potential risk. Our study results showed that IARC needs to improve their scientific communications.

How should risk be communicated to children: a cross-sectional study comparing different formats of probability information

BACKGROUND

Newborn screening, which identifies inherited disorders and sometimes carrier status, will increasingly involve health professionals in the provision of appropriate information and support to children and their families. The ability to understand carrier results relies on an understanding of probabilistic terms. However, little is known about how best to convey probabilistic medical information to children. Research with adult populations suggests information format significantly affects comprehension. This study aimed to explore which presentation format is most effective in conveying probabilistic information to children.

METHODS

A probabilistic task based on the cup game was used to measure which of five different formats was associated with greatest understanding in children aged 7-11 years old (n = 106). Formats used were verbal labels (e.g. rarely, sometimes), percentages, proportion-word (e.g. 1 in X), proportion-notation (e.g. 1:X) and pie charts. There was also an additional mixed format condition. In each trial a picture was presented of three cups, each with a different probability depicted beneath it, and the child was asked to select which cup was most likely to contain the ball. Three trials were presented per format. Children also rated how certain they were that they had answered correctly.

RESULTS

There was a significant relationship between format and comprehension scores. Post hoc tests showed children performed significantly better when probability was presented as a pie chart, in comparison to percentages, proportion-notation, proportion-word and mixed format trials. Furthermore, most children (84%) got all trials correct for this format and children were significantly more certain that their response was correct in the pie chart trials compared to all the other formats (p < 0.001). Significant positive correlations were found between self-ratings of certainty and comprehension of verbal labels, percentages and pie charts. Older age was also associated with better performance on all formats except percentages. Overall comprehension was calculated by summing the scores for the individual trials and this was independently associated with older age and higher IQ.

CONCLUSION

The results suggest that 7-11 year olds can understand probability information, but that the format used will significantly affect the accuracy and confidence with which children in this age group make judgements about the likelihood of an event. Of the formats studied, pie charts appear to be the optimal method of presenting probabilistic information to children in this age group. Health professionals and designers of health messages should be cognisant of this when communicating medical information to children aged 7-11 years old.