Applies to: @RISK for Excel 5.x and Up

 

Why do I see “Error” for some iterations in one or more outputs?

In the @RISK Data window, each row represents an iteration and each column represents an input or output. If you see “Error” in this window, it means the formula for that output (or a referenced cell) evaluated to an Excel error during that iteration.

• The error may not be in the output cell itself, but in any upstream cell it depends on. In Excel, when one cell has an error, all cells that reference it inherit that error.

This can happen even if no errors appear when a simulation is not running.

For example, a cell with RiskNormal(10,3) has a static value of 10, so no error is visible.

• But during simulation, that distribution can return a negative value.
• If another cell takes the square root of that value, Excel will generate a #NUM! error for that iteration, and any output depending on it will show “Error” in the Data window.

How to find the source of the error:

1. In the @RISK ribbon, go to Results and click Simulation Data (the xᵢ icon).

2. Find the output column and the iteration row that shows “Error”.

3. Click that cell, then click the footprint (shoeprint) icon at the bottom of the window (“Update Excel with values from the selected iteration”).

4. @RISK will restore the workbook to the exact state of that iteration.

5. Inspect the error cell and trace back through its formulas to find the cause.

6. Click the footprint icon again or close the Data window to return to normal.

 

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