For branching situations, where the condition that you need to test involves responses to other questions or the values of system variables, you may define an IF Condition (also known as a Complex Skip condition), which is based on a Filter.
The IF Condition (Filter) is attached to a question, and the execution of the skip is conditional upon the result of logical or algebraic combinations of responses to several previous questions. The condition will be evaluated on arrival at and before displaying the question which includes the skip. If the result is TRUE, the skip is performed and the current question is not displayed. If the result is FALSE or missing value, the skip is not performed.
You can select functions, system variables, and operators directly from the If field. Simply right-click in the field to display the floating menu.
For defining the Filter for an IF Condition, there are three basic types of expression:
Discrete expression
Literal expression
Algebraic expression
These expressions may be combined with boolean operators.
Note: Filters can also be used in Field tools (Extract. Browse and Quotas). In these tools, however, the syntax for the expressions is a simplified subset of the expressions used in Design. See Filter expressions in Field tools.