You can use the Edit Derived Category dialog to enter the calculation for a category that derives its value from that of other categories in the variable.

To open the Edit Derived Category dialog, create a derived category using the Insert Categories dialog, and then click Edit Item.

The left of the dialog displays the name of the variable, and lists all the categories in the variable. Drag categories from this list into the box on the right of the dialog to add them to the expression for the derived category.

You can also add to the expression by typing directly into the box, or by copying and pasting all or part of the expression from another application such as Notepad.

Derived categories use an arithmetic expression based on the values of other categories in the table. This differs from using an expression in a user-defined category, which uses a logical expression that tests the case data to determine whether a respondent is included in the count.