Simulation Master Tutorials > Running a Simulation (Standard Edition) OR Running a Simulation (Premium Edition) > Correlated Inputs

*This tutorial is completed using Simulation Master Premium Edition. It also applies to the standard edition, however the ribbon menu and simulation form will have a different appearance.*

Simulation Master allows for correlation of random variable inputs. For more detailed discussion of correlated inputs refer to this blog article.

To account for input variable correlation, a correlation matrix must be added to the worksheet containing the output cell. Click the *Correlation matrix* button on the ribbon.

The correlation matrix form will appear. It will show all random variables located on the worksheet containing the output cell. All correlated variables must be located on the output cell worksheet.

Variables can be removed from the matrix by selecting from the list and clicking the *Remove Variable* button. This only omits the variable(s) from the correlation matrix, and does not remove them from the model worksheet.

The correlation matrix must be placed in a blank area of the worksheet. To place the matrix, click the minimize button next to the upper left cell location box.

When the correlation matrix form is minimized, click the cell where the upper left cell of the matrix will be located.

Once the cell is selected, click *OK* and the correlation matrix form will reappear. Click the *Create* button to insert the matrix.

The matrix will appear with the selected variables on the left and top sides. These cells should not be modified because the software uses these addresses when running the simulation.

The diagonal values must be 1. Enter the Spearman Rank correlation coefficients in the lower triangular area of the matrix. The upper triangular area does not need to be populated.

We are now ready for simulation. Click the *Run Simulation* button on the ribbon. The start simulation form will appear.

Click the *Correlated inputs* checkbox. To select the matrix, click the minimize button next to the select correlation matrix box.

Select the entire matrix including left and top headings. Click *OK* to return to the start simulation form.