Managing products and portfolios : Investment analysis : Specifying estimates : Defining variables
  
Defining variables
Define project-wide global variables and variables that change over the timeline of your project, and use these variables in calculators. These variables can be applied across the model. For example, you can define the price per unit for a product by using the project variables.
Procedure
1 On the Variables tab, use the command line or the Add variable button.
2 Specify a name for the variable. You can define complex project variables as you create complex calculations in the calculator.
3 Select a type for the variable and a value.
 
Type
Action
Fixed
Specify the actual value for the variable. For example:
Price = 600
Normal
Specify a mean value and its standard deviation. For example:
costPerUserProject = N(100,10)
Triangular
Specify a low, likely and high value. For example:
numUsersProject = T(1000,1500,2000)
Formula
Specify a function of other values that are already defined. For example:
costProject = numUsersProject * costPerUserProject
4 To use any of these variables, on the Calculator tab and within a calculator tape, refer to the names of the variables. For example:
numUsersLocal = T(300,350,400)
costPerUserLocal = N(50,2)
costLocal = numUsersLocal * costPerUserProject
costTotal = costLocal + costProject
Within a tape, if you define a local variable with the same name as a variable, the local variable masks the variable.
5 Click Run Simulation.
The distribution of all random variables is sampled and found through Monte Carlo simulation.
6 To save the variable as the default variable for all elements that you create, click Save as Default.
If a default variable is already present, the existing variable is overwritten by the new default variable. Default variables are applied to new elements only.
7 Click OK.
See also
Specifying estimates