Re context, see see the following two extract from
Event Context Overview and Event context: Occurrence in data
Situations in which Event context is not used include:
Any modification to the EHR which corrects or updates existing content, including by administrative staff, and by clinical professionals adding or changing evaluations, summaries etc.
Patient-entered data where no interaction with health professionals took place; typically readings from devices in the home such as weighing scales, blood glucose measuring devices, wearable monitors etc.
In this example, a Contribution is made to the EHR, consisting of one or more Compositions that were each created or modified due to some clinical activity. Within such a set, there will usually be one Composition relating directly to the event, such as the patient contact - this is the Composition containing the doctor’s observations, nurses’ activities etc, during the visit, and is therefore the one which contains the
EVENT_CONTEXT instance. Other Compositions changed during the same event (e.g. updates to medication list, family history and so on) do not require an Event context, since they are part of the same Contribution, and the event context of the primary Composition can always be retrieved if desired.
So far what the specs offer on context being optional…I assume however this could also have been modelled differently in a way that the context is always mandatory.
Re content, see the following extract from
it may be empty. Although for most situations, there should be content in a Compostion, there are at least two cases where an empty Composition makes sense:
the first is a Composition in 'draft' editing state (VERSION.lifecycle_state = 'incomplete')
the second is for systems that are only interested in the fact of an event having taken place, but want no details, such as so-called clinical 'event summary' systems, which might record the fact of visits to the doctor, but contain no further information. This can be achieved using Compositions with event context, and no further content.
My take is that the first use case is a general one and would not justify content to be optional. The second one is a use case I guess, albeit a somewhat feeble one.