There are various proposals to change HISTORY<T>, as follows:
instead of using origin & offsets, use absolute times in each EVENT
remove SINGLE_EVENT and simplify class structure back to just
HISTORY and EVENT
make it optional (AG) because many instances of OBSERVATION will
not specifically record their own observation time - they
'inherit' the time of the clinical session. (TB: I agree with
the point - in today's GP consults - since there is almost no
automated recording of anything, but disagree with the solution.
Recording of observation time is essential, and even if the
absolute times of multiple observations in a GP consult are
uninteresting, the order may be significant.
A further requirement which has come to light during archetype
and system-building in Australia is that state:ITEM_STRUCTURE
should be available on EVENT, since it is usual to record
state at the time of the data event, rather than as a separate
time series on OBSERVATION, which it is currently. The latter is
not incorrect and should be retained; but the addition of EVENT.state
will handle the more common clinical cases.