The onoccchange statement declares that the statements following it are executed at the time that a group's current occurrence changes. The onoccchange statement can only be coded in a group: a roster or a multiply occurring form.
During data entry, whenever the user moves from one occurrence to another (forward or backward), the onoccchange of the group will be executed.
The onoccchange statement is not very common, but it may be useful in some CAPI applications, particularly to set question text fills.