It is critical that there be as much transparency as possible with respect to computations that underlie the variables chosen for display. In a large, integrated model, achieving such transparency is not simple. You are invited to look at the very extensive Help section called “Understanding the Model: ‘Opening the Black Box’” for extensive documentation via flow charts, equations, and computer code.

While working with display of variables, however, there are several ways in which to drill down for explanations of what lies behind their computations. You can generate a pop-up box with those modes of drilling by clicking at several locations:

On any variable name in the Status box of the variable selection form (either the Standard Variable Selection or the Full Variable/Parameter Selection form) or on the Display Menu.

On the column of any variable displayed in a table.

Although there are minor variations, the pop-up box will include some or all of the following options for learning more about the variables:

Define. Provides a pop-up window with a longer definition of the variable(s).

Explain. Provides (in most, but not all cases) a topic from the help system with a causal diagram that includes the variable and shows how it relates to other variables in the model. There normally is also textual explanation.

View Equations. Provides (in most, but not all cases) a topic from the Help system with a set of equations that includes the variable and related ones, along with textual explanation.

View Code (not always available). Provides (in most cases) a window showing the computer code (Visual Basic) that is used to compute the variable.

Drivers. This option opens a new Form called Drivers that provides a great deal of information. First, the form will pop-up with a diagram showing the variable in the center and the variables from which it is computed on the left plus the variables to which it contributes on the right. This drivers diagram is derived directly from parsing the computer code of the model. If you float the cursor over any variable name on this screen, a more extended name will pop up. If you click on any driver variable or driven variable, the diagram will repaint with the variable selected at the middle. The menu option named Options has sub-options that allow you to display the computer code, view the equations, or see a causal diagram, view equations, or display the computer code (just as do the options from the pop-up box itself). It is also possible to save the drivers diagram to the clipboard or to a file – or to print the diagram.