Men's interpretations of graphical information in a videotape decision aid

Data display format and hospital ward reports: effects of different presentations on data interpretation

BACKGROUND

Graphs are often used in medical communication, both in clinical practice and health management. They can help the processing of quantitative information but may also contribute to drawing wrong conclusions. The aim of the survey is to study the graphical perception of the data at the management level and its possible effects, showing how some criteria of appraisal of a phenomenon are influenced by the graphical format.

METHODS

One hundred and five medical doctors and health direction professionals of hospitals in Naples, Rome, Siena and Turin were interviewed. Four different graphs or table related to the same hypothetical data on average hospital stay in the period January 2000 to September 2003 were shown to participants, and their impressions were recorded.

RESULTS

Less than one-fourth of the participants understood that the data set was the same for the different diagrams. The process of understanding is mostly correlated with being a director, having a degree in medicine and working in central-northern cities. The table seems easier for interpretation (98.1%), more suitable (84.8%), more used (92.4%) and more pleasant than other data presentation. On the other hand radar format had worse results in all questions.

CONCLUSIONS

The choice of a graphical format may influence the understanding of data. Further research is needed in order to sustain the improvement of medical and health professionals' knowledge in the display data format.

Why not? - Communicating stochastic information by use of unsorted frequency pictograms - a randomised controlled trial

OBJECTIVE

Statistical health risk information has been proven confusing and difficult to understand. While existing research indicates that presenting risk information in frequency formats is superior to relative risk and probability formats, the optimal design of frequency formats is still unclear. The aim of this study was to compare presentation of multi-figure pictographs in consecutive and random arrangements regarding accuracy in perception and vulnerability for cognitive bias.

METHODS

A total of 111 patients with multiple sclerosis were randomly assigned to two experimental conditions: patient information using 100 figure pictographs in 1) unsorted (UP group) or 2) consecutive arrangement (CP group).The study experiment was framed as patient information on how risks and benefit could be explained. The information comprised two scenarios of a treatment decision with varying levels of emotional relevance. Primary outcome measure was accuracy of information recall (errors made when recalling previously presented frequencies of benefits and side effects). Cognitive bias was measured as additional error appearing with higher emotional involvement. The uncertainty tolerance scale and a set of items to assess risk attribution were surveyed.

RESULTS

The study groups did not differ in their accuracy of recalling benefits, but recall of side effects was more accurate in the CP-group. Cognitive bias when recalling benefits was higher in the UP-group than in the CP-group and equal for side effects in both groups. RESULTS were similar in subgroup analyses of patients 1) with highly irrational risk attribution 2) with experience regarding the hypothetical contents or 3) with experience regarding pictograph presentation of frequencies. Overall, benefit was overestimated by more than 100% and variance of recall was extremely high.

CONCLUSIONS

Consecutive arrangement as commonly used seems not clearly superior to unsorted arrangement which is more close to reality. General poor performance and the corresponding high variance of recall might have clouded existing effects of the arrangement types. More research is needed with varying proportions and other samples.

The impact of the format of graphical presentation on health-related knowledge and treatment choices

OBJECTIVE

To evaluate the ability of six graph formats to impart knowledge about treatment risks/benefits to low and high numeracy individuals.

METHODS

Participants were randomized to receive numerical information about the risks and benefits of a hypothetical medical treatment in one of six graph formats. Each described the benefits of taking one of two drugs, as well as the risks of experiencing side effects. Main outcome variables were verbatim (specific numerical) and gist (general impression) knowledge. Participants were also asked to rate their perceptions of the graphical format and to choose a treatment.

RESULTS

2412 participants completed the survey. Viewing a pictograph was associated with adequate levels of both types of knowledge, especially for lower numeracy individuals. Viewing tables was associated with a higher likelihood of having adequate verbatim knowledge vs. other formats (p<0.001) but lower likelihood of having adequate gist knowledge (p<0.05). All formats were positively received, but pictograph was trusted by both high and low numeracy respondents. Verbatim and gist knowledge were significantly (p<0.01) associated with making a medically superior treatment choice.

CONCLUSION

Pictographs are the best format for communicating probabilistic information to patients in shared decision making environments, particularly among lower numeracy individuals.

PRACTICE IMPLICATIONS

Providers can consider using pictographs to communicate risk and benefit information to patients of different numeracy levels.

Numeracy and communication with patients: they are counting on us

Patient-centered interactive communication between physicians and patients is recommended to improve the quality of medical care. Numerical concepts are important components of such exchanges and include arithmetic and use of percentages, as well as higher level tasks like estimation, probability, problem-solving, and risk assessment--the basis of preventive medicine. Difficulty with numerical concepts may impede communication. The current evidence on prevalence, measurement, and outcomes related to numeracy is presented, along with a summary of best practices for communication of numerical information. This information is integrated into a hierarchical model of mathematical concepts and skills, which can guide clinicians toward numerical communication that is easier to use with patients.