Percent as DV_PROPORTION or DV_QUANTITY

Hi all!

This is a conundrum we’ve been talking about informally for a long time, but never really concluded. openEHR has two possible ways of representing a percentage:

  1. DV_PROPORTION with type = 1
  2. DV_QUANTITY with unit = %

We haven’t been clear on which one of these should be used for which use cases. I have a hypothesis which I’d like to get some input on:

  1. When we’re talking about physical concentrations such as saline concentration or oxygen saturation we should probably use DV_QUANTITY with units of %, [ppth], [ppm] or [ppb].
  2. When we’re talking about abstract or otherwise unitless concepts such as percent weight change over a time interval, or measured/predicted FVC, it’s probably more reasonable to use DV_PROPORTION.

Thoughts?