Representation of scales total score meaning


We are working with the International prostate symptom score (IPSS) archetype from CKM. We have been asked to add the interpretation for the total score, which ranges from 0 to 35 and that is currently represented as a DV_COUNT:

  • 0-7: Mild
  • 8-19: Moderate
  • 20-35: Severe

We have several options here.

This approach also follows the recommendation of not adding additional elements to scores
The problem with this approach is that we lose the formalization of that knowledge.

In this specific example we see a problem with relying on an ad hoc interpretation of those ordinal values, as it defines a kind of ranges but not explicitly (it only includes an option for 10, 15 and 20). The alternative here would be to explicitly define a DV_ORDINAL for each of the possible values (for example, from 0 to 35 in the IPSS score), but this seems difficult to maintain.

  • Option 3. Is defining the value of a total score as a DV_COUNT mandatory in current modelling patterns? If not, would it possible to define a total score directly as a DV_ORDINAL/DV_SCALE?

As an additional note, technically it would be possible to define a range as the constraint of the DV_ORDINAL value, as it is just an integer. We can do this in LinkEHR but I can’t see that possibility in the Archetype Editor. Something like this:


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Hi David,

The inclusion of a coded interpretation or grade in addition to the raw total count is quite a common pattern.

My current approach would be

  1. Keep the Total Score as a Count

2 Add a Grade/Interpretation as a DV_CODED_TEXT (not an Ordinal/Scale).with internal codeList Mild, Moderate , Severe. The algorithm for calculating the Intepretation can be descriped in the description, or better still add

From what I can see, that Interpretation is part of the original score

I was the original author of the Waterlow scale and would not use an ordinal it that way now.
Originally there quite a few places where ‘artificial’ ordinals were created but I think that approach is not used exactly for the reasons you have given.


Aslo - I’d suggest you make a change request on CKM for the Interpretation to be added.


I can also see the benefits of that new approach using a DV_CODED_TEXT. Thus, we do not need to replicate the value of the total score as it happens when using a DV_ORDINAL, which is safer from a data perspective.