# Sensi Specs

Sensi Specs... calls forth the dialog shown in Figure 3-23. This dialog enables you to establish the characteristics for a set of sensitivity runs. It also enables you to "turn on" sensitivity analysis.

Figure 3-23 Sensi Specs Dialog

The top of this dialog contains an Allowable list and a Selected list, as well as arrowed Enter (>>), Remove (<<) and Replace (<->) buttons. In the middle of the dialog is a box for specifying the number of sensitivity runs you want to make, a set of controls for varying a selected variable in the Selected list, a Set button, and a list of values associated with the selected variable. In the bottom left of the dialog are buttons which automatically take you to the Graph Pad and Table Pad objects when you leave the dialog. In the bottom right is a check box for turning Sensitivity On on, a check box for printing sensitivity setups along with comparative graphs and tables, a Cancel button, and an OK button.

Entering, removing, and replacing variables works exactly as it does in the Define Graph... and Define Table... dialogs described in Chapter 6. Simply select the target variable(s), and click the appropriate button between the Allowable list and Selected list. Once in the Selected list, variables are available to have their values changed from run to run in the sensitivity analysis. Note that when you enter a variable into the Selected list, its current initial value is shown within parentheses.

When you select any variable that has been entered into the Selected list, you can then define how its values will vary for the purpose of sensitivity analysis. You have three choices in the Macintosh version: Incremental, Distribution, and Ad Hoc; and a fourth in the Windows version: Import Data. Once you have selected the variation type you wish to use, you will be prompted to provide specifics of the variation. Different Variation Types are shown in Figure 3-24.

Figure 3-24 Sensitivity Analysis Variation Types

When you change the "# of Runs" you wish to make, the values of the variables that you have specified as candidates for variation will automatically be changed (except in the case of ad hoc specification, in which case the last value specified will be used for any additional runs you specify). "# of Runs" cannot be selected after importing data through the Import Data option (Windows) because that number is determined by the number of values pasted into the sensitivity setup.

Helpful Hint: If you have created a sensitivity setup, depressing the alt key (Windows) or the option key (Macintosh) as you choose the Run menu will change the display of the Sensi Specs... item to Disable Sensi Run or Enable Sensi Run. Thus, by depressing the alt or option key while choosing the Sensi Specs... item from the Run menu, you can toggle between Sensitivity On and Sensitivity Off without entering the Sensi Specs... dialog.