HomeTroubleshooting@RISK for Excel: Other IssuesResults Not as Expected (Debugging Tips)

8.1. Results Not as Expected (Debugging Tips)

Applies to: @RISK 5.x–7.x

Contents:
"Errors" that really aren't?
Error message appears?
Output has just one value?
No values to graph?
Calculations seem wrong
Visual Basic errors?

See also:
"No inputs found that affect this output" instead of Tornado Graph

My simulation results in @RISK don't seem right. Can you recommend any techniques for finding my mistakes in my model?

Consider the possibility that your model is actually behaving correctly. We're frequently asked about these "errors", but they make sense when they're explained:

If an error message appears, there's probably an explanation and a fix in the Troubleshooting section of this Knowledge Base. Type a few key words in the search window at the bottom of this page.

My output graph is just a vertical line, and the statistics table shows minimum = mean = maximum.

This output has the same value in every iteration. Most likely, that means none of your input distributions are precedents of this output.

An input distribution shows "no values to graph", or it shows a graph but the statistics table shows that some iterations were errors.

Take a look at the cell that contains the distribution. Many people assume that the values shown on a histogram, or in the Data Window, are values of the cell, but actually they're the values of the distribution within the cell. If some logic causes the distribution to be skipped in some iterations, then @RISK records a value of "Error" for the distribution during those iterations. For example, suppose that the cell formula is

=IF(A15>0, RiskTriang(100,200,450), 0)

By this logic, a value is drawn from the distribution when A15 is greater than 0, but not when A15 is less than or equal to 0. In each iteration when A15 ≤ 0, @RISK records "Error" because the distribution is not called and therefore has no value.

If you actually want @RISK to record the values of a cell formula, and not just the values of a distribution within the cell, wrap it in a RiskMakeInput function, like this:

=RiskMakeInput( IF(A15>0, RiskTriang(100,200,450), 0) )

An output shows "no values to graph", or it shows a graph but the statistics table shows that some iterations were errors.

Either way, here are some tools:

Numbers seem wrong in my calculated results.

Here are some suggestions. (Save the workbook under a new name before you make debugging-type edits.)

I think my worksheets are okay, but my VBA code isn't working right.

Debugging Visual Basic for Applications code can be tricky. Here are some hints:

Can you look at my model and tell me what's wrong?

We're sorry, but the scope of free Tech Support services doesn't include debugging customer models. If you have a question about how a particular @RISK feature works, or if @RISK is not behaving correctly, Tech Support will gladly help. If you want a more detailed review or audit of your model, please ask your Palisade sales manager to book some time with one of our custom developers or industry consultants.

Additional keywords: Precedent and dependent cells, precedent and dependant cells

Last edited: 2019-02-22

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