NullFlavor on Intervals of time

Jun 27, 2013

Here’s a sample that I see fairly often: ````


Taken at face value, this is a claim that the episode of healthcare that this CDA document happened before time began. Or, at least, prior to the [big bang](http://www.afr.com/p/national/rudd_revenge_gillard_gone_oVg8nYB5lGzC2WkcTa346I) (link for my Australian reader's amusement). This variation claims that it started then, and is still happening:

````

But that’s probably not what this is trying to say either.

This table summarises what I think are the likely things you’d want to say with regard to nullFlavor on IVL: