An IVES Event can consist of multiple performances of the same conceptual event. While the event may remain consistent, the performances may have differences from performance to performance. IVES attempts to make it as concise as possible for defining the behaviour of performances in as concise a manner as possible by utilising cascading of values for the items that can change from performance to performance.
In choosing which values are able to cascade we have worked on the assumption that the primary thing that is going to change is location of the performance, ie the venue. As an event moves between different venues it may well also change the admission cost and the duration of the performance may change as well.
All of these values may be defined on the <Event> itself. If they are not defined anywhere else, then all of the <Performance> elements that are included will all share the same values that are defined on the <Event>.
If you have a group of performances that differ from the default values defined on the <Event> then you should group all the <Performance> elements under a single <Schedule> and define the differences from the <Event> on the <Schedule>. All of the <Performance> elements that are contained within the <Schedule> will utilise the values defined on the <Schedule> and if they are not defined then the values utilised on the <Event> should be utilised.
It is possible that you have a single <Performance> that differs from the other <Performance> elements within a <Schedule>. Rather than defining a new <Schedule> to contain the single <Performance>, it is possible to override the values on a single <Performance>.
Therefore if you want to find out the behaviour of a particular <Performance>, then you should first check to see if there is a value defined directly inside the <Performance>. If it is not defined then you should use the value defined within the <Schedule>. If this is not defined then you should utilise the value defined within the <Event>. If this is not defined then the value is undefined for the <Performance> in question.