I missed the initial meetings and wanted to provide one comment after studying the slides.
Another type of metadata are historical facts about organization. E.g., XeiserFenente transitioned from EHR A to EHR B on May 7th, 2001
Or, XeiserFenente acquired 1 new big hospital on June 1, 2007 - hence more admissions are recorded. (assuming encounter locations are not in the data)
There was epidemic of Ebola starting on date xyz. (which annotates the data) (100% change in monthly trend is explained by this - it is not an error)
Since June 7, 2016 - we link mothers the babies and we use this EHR mechanism or this Payor-based data mechanism
So statements about a single concept (new death type introduced), about trends, but also about the institution (or location or environment) which generated the CDM data.