Tables or bar graphs? Presenting test results in electronic medical records

Electronic personal health records offer a promising way to communicate medical test results to patients. We compared the usability of tables and horizontal bar graphs for presenting medical test results electronically.

We conducted experiments with a convenience sample of 106 community-dwelling adults. In the first experiment, participants viewed either table or bar graph formats (between subjects) that presented medical test results with normal and abnormal findings. In a second experiment, participants viewed table and bar graph formats (within subjects) that presented test results with normal, borderline, and abnormal findings.

Participants required less viewing time when using bar graphs rather than tables. This overall difference was due to superior performance of bar graphs in vignettes with many test results. Bar graphs and tables performed equally well with regard to recall accuracy and understanding. In terms of ease of use, participants did not prefer bar graphs to tables when they viewed only one format. When participants viewed both formats, those with experience with bar graphs preferred bar graphs, and those with experience with tables found bar graphs equally easy to use. Preference for bar graphs was strongest when viewing tests with borderline results.

Compared to horizontal bar graphs, tables required more time and experience to achieve the same results, suggesting that tables can be a more burdensome format to use. The current practice of presenting medical test results in a tabular format merits reconsideration.