Action-based vs. result-based properties of Observations

Background

Tom wrote:

The dual nature of HL7v3 Acts becomes most apparent in Observations, where we not only collapse action and statement about the action into one object, but also the action and its result. In Patient Care, I explained that they have been using negationInd the wrong way (i.e. they used it to negate the result instead of the act of observing it).

I then realized that we have the same issues with some associated observations, most notably the Severity that is often associated with Observations. The severity is not a statement about the observation itself, but only about the value/result. It doesn´t say that my diagnostic judgment was an arduous task, but that the diabetes I diagnosed was of a severe nature.

This then leads back to something I have been proposing before... we would greatly benefit from having a separate classCode for ´asssertions´, i.e. statements about the existence of some feature of reality, most notably about the presence of a certain disease in a patient. In Patient Care, the idea came forward to have such a class and give it a specialized attribute ´severityCode´ that would mean exactly what a severity Observation is supposed to mean now. The proposed name for this specialization of OBS would be (Diagnostic) Judgment.

Gunther wrote:

An observation and it's result are inextricably linked.

But we will have to talk about the different ways that observation is used and abused. Once that is cleared up (realistically clearing this up is as nice to have as it is impossible), we *MIGHT* say that there are two stages in an Observation:

- an action to find an answer
- the answer found through the action.

The action defines what you can find. If you read a meter you find numbers. If you ask a yes-no-question you find yes or no. If you ask an open question you find free text. If you look at this text finding features you find features in the answer. If you look for shapes under a microscope you find shapes.

There is no statement of a result that can stand without also saying what was done to get that result. Do heights not exist without people measuring them? They may or may not, we don't need the scholastic dispute, but what matters is that if you speak about height, you have to say what height and at least roughly how it was measured. You cannot even think of an abstract height without considering how you would measure it. Metrology tells us that measured properties are to be defined in an operational manner (operational is just a synonym for actionable, i.e., no property without the possibility of a measurement act.)