====== Tornado chart ======

A tornado chart ranks the importance of the simulation inputs (parameters) on a specified output (at a specified timepoint). The rank coefficient for each input is represented by a horizontal bar with a value between -1 and 1, ordered from highest to lowest contribution to the output variability.

The tornado chart is a tool in sensitivity analysis and can only be created after a probabilistic simulation or a sensitivity analysis has been performed.

Tornado charts can help you:

  * Find which parameters affect a specific simulation output the most (and the least).
  * Illustrate correlations between parameters as set up in the [[Probabilistic_settings|parameter correlation settings]].

===== Creating a tornado chart =====

From the [[Results_window|results window]] (Recommended)

  * Right-click an output that you wish to plot and select **Tornado Chart** from the popup-menu.

From the [[Charts_window|charts window]]

  * Right-click the charts window and select **Create | Tornado Chart** from the popup-menu.

===== Editing a tornado chart =====

Some properties can be changed directly by using the controls below the chart. For a tornado chart there are controls for:

  * **Legend** - Toggle legend on/off
  * **Correlation** - Select ranking method (more information can be found below).
  * **Time-point** - Select time point for the output.

To change other properties either right-click the chart in the [[Charts_window|charts window]] and select **Edit**, or double-click the chart, or click the {{:Edit24.png|Edit}} button in the title bar.

The chart editor has two tabs:

==== Properties ====

This screen let you edit properties such as name and axes, that are common to most charts. Please see [[Editing_chart_properties|editing chart properties]] for more information.

==== Data ====

  * **Output** - Select the target output.
  * **Inputs** - Select the inputs you are interested in. By default all parameters that are included in the probabilistic/sensitivity analysis are selected.
  * **Timepoint** – For time dependent outputs, specify the time point you wish to plot.\\

  * **Max number of bins** – Limits the number of inputs that are shown in the chart. //Default=10//.
  * **Type** – Select which correlation ranking method you wish to use.
    * Spearman’s rank correlation coefficient
    * Pearson product-moment correlation coefficient
    * Standardized regression coefficient
    * Standardized rank regression coefficient
    * Partial correlation coefficient
    * Partial rank correlation coefficient

===== See also =====

  * [[Charts_window|Charts window]]
  * [[Results_window|Results window]]