Applies to: @RISK 5.x and Up

Tornado Chart Shows Non-Precedent Inputs

 

Issue:
One or more bars on a tornado chart represent an input that is not actually a precedent of the output.

Causes:

1. Smart Sensitivity Analysis Disabled

   • Check whether Smart Sensitivity Analysis is enabled on the Sampling tab of Simulation Settings.

   • If enabled, the simulation should only include actual precedents of the output as bars.

   Exception:

   • Some Excel features (listed in Precedent Checking) prevent Smart Sensitivity Analysis from tracing all precedents.

   • @RISK displays a pop-up at the start of the simulation if this occurs, asking whether to proceed without Smart Sensitivity Analysis.

   • If you have Smart Sensitivity Analysis enabled and did not see this pop-up, the most likely explanation is that a dependent relationship exists.

   Finding Precedents or Dependents in Excel:

   • For Excel 2007–2016, you can use Trace Precedents or Trace Dependents:

     • Click the output cell, then repeatedly click Trace Precedents to locate the input in question.

     • Or click the input cell and click Trace Dependents to find the output (or a recognized precedent).

     • Which method is easier depends on whether there are more direct/indirect dependents or precedents.

   • If the precedent/dependent is on another worksheet, Excel shows a dotted line with a worksheet icon. Click the dotted line (not the icon) to follow the relationship.

2. Duplicate Input Names

   • If two or more inputs share the same name, the tornado might display the wrong one.

   • Check in the Model Window to see if the name occurs multiple times.

   • If displaying inputs by category:

     • Right-click in the table → Arrange → uncheck Group Inputs by Category.

   • To sort by name: click the gray Name column header to sort A–Z or Z–A; duplicate inputs appear next to each other.

   • To rename an input: right-click it → Function Properties → change the name.

Summary:
A tornado bar appearing for a non-precedent input is usually due to either Smart Sensitivity Analysis being disabled or duplicate input names. Use Excel’s Trace Precedents/Dependents and verify input names to resolve the issue.