A tornado diagram (given this name due to its resemblance to a tornado) is a graphical method for displaying a series of univariate (or one-way) sensitivity analyses that has been commonly used in cost-effectiveness analysis. Figure 1 shows an example of a tornado diagram—with incremental cost-effectiveness value ranges arranged from the largest at the top to the smallest at the bottom. In a tornado diagram, the effects of individual parameter variation on results can be compared visually, allowing analysts to intuitively communicate which parameters are more sensitive to variation— that is, parameters whose variation has the greatest effects on the results of the analysis. In the example shown in Figure 1, individual variation of Drug A costs has the greatest effects on model results, and ...