Applies to:
@RISK, all releases
RISKOptimizer, all releases
@RISK Developer's Kit (RDK), all releases

Why is the expected value displayed in a cell with an @RISK input different from the mean of the simulation results for that input?

Answer:
This is normal statistical behavior. The simulated mean will usually be close to, but not exactly, the theoretical mean.

• The same applies to standard deviation, median, mode, percentiles, and other statistics.

The difference often comes from Simulation Settings.

In Simulation Settings » When a Simulation is Not Running, ensure Static Values is selected, and for "Where RiskStatic is Not Defined, Use," set True Expected Values.

• If a RiskStatic property is present, it overrides these settings and displays the RiskStatic value instead of the expected value.

To get the theoretical mean rather than the mean from the last simulation, use RiskTheoMean().

• Similarly, use RiskTheoStdDev(), RiskTheoPercentile(), and other "Theo" functions to retrieve theoretical statistics in your worksheet.

 

Related Articles:

Static Value of Output Differs from Simulated Mean

Setting the "Return Value" of a Distribution