Validity periods define the lifespan of an object or infotype record, or the period of time when they officially exist. You specify a validity period by providing a start date and end date when you create objects and infotype records.
Period of time (in months and years) in which attendance of an event type is deemed to be valid as a prerequisite for attendance of another event.
In Training and Event Management, prerequisites for business event attendance are represented by qualifications (from the Personnel Development component) and by business event types. Attendance of business event types is considered a qualification. The validity of such qualifications can expire just as the validity of other qualifications or skills does.
Once the validity period expires, the relationship between the attendee and the business event type ('has attended') becomes invalid. This relationship is created during follow-up processing for the business event.
Note that the validity period of qualifications and event types has nothing to do with the validity period of objects and infotype records, which defines the period of time during which an object or record exists. This information is stored with the object/infotype itself with a start and end date.