Applies to: @RISK 7.5.0 and Up

Contribution to Variance Tornado Values

 

How can I get the Contribution to Variance tornado values into my worksheet?
You can retrieve Contribution to Variance values directly into worksheet cells by using the RiskSensitivity function. Support for Contribution to Variance was added to this function when the tornado graph was introduced in @RISK 7.5.0.

 

Which RiskSensitivity arguments are used for Contribution to Variance?
Contribution to Variance is selected by setting the fourth argument of the RiskSensitivity function to 4. The fifth argument then determines what information is returned.

Use these patterns:

• RiskSensitivity(output, , k, 4, 1)
  Returns the name of the k-th most significant input.

• RiskSensitivity(output, , k, 4, 6)
  Returns the percentage of total variance contributed by the k-th most significant input.

• RiskVariance(output) * RiskSensitivity(output, , k, 4, 6)
  Returns the actual variance contributed by the k-th most significant input, rather than the percentage.

 

What do the arguments mean?

• output: The output cell reference or name

• simulation number: Omitted to use simulation 1

• k: Input rank (1 = input with the greatest contribution to variance)

• 4: Specifies Contribution to Variance

• 1 or 6: Specifies whether to return the input name (1) or percentage of variance (6)

 

Is there an example?
Yes. In the attached example workbook, after running a simulation, the contribution-to-variance values appear in cells O9:Q15, and the corresponding tornado graph is shown for reference.

 

Attachments:
KB1528_RiskResultsGraph and RiskSensitivity.xlsx