Visualization for better understanding global sensitivity analysis results: The case of safety assessment of radioactive waste disposal.

Sensitivity analysis answers questions about the influence of parameters on the simulation results and plays a significant role in the development of environmental models by helping to understand the relations within the model and test its adequacy. Comparison of various sensitivity analysis approaches is often also quite useful because different methods employ different measures for ranking model parameters and their unconformities and disagreements provide additional information on model behavior. The visual representation of numerical results is crucial for their correct interpretation, and at first sight, the visualizations for the sensitivity analysis should be quite universal because in most cases an outcome of sensitivity analysis is the same: a set of indices measuring the significance of model inputs for the selected output. Surprisingly, it is not so straightforward. This paper compares visualization types suitable for the graphical representation of the sensitivity indices and demonstrates their benefits and caveats in different cases.