A metric is something you measure, so it should depend on the measurement circumstances.
The way you describe these circumstances could be stored and managed master data, which would be used as a tool to conform the description of the measurement.
That said, of course numeric values can represent attributes/features of objects/states etc.
Think about a location dimension(latitude,longitude,postal code, street adress number) or products (width,length, depth, weight) as an example.
Therefore numeric values can be stored and managed as master data also.
I hope this helps.
With kind regards,