Class vs property

[jiteshjosh8]

I feel that some entities should be data property instead of Class. For example : "official title of clinical trial" is a subclass of "title of clinical trial". It means when we use this ontology to define a RDF graph, we have to create an instance of this class to put value for a specific "study". So does it make sense to create a instance for such properties?
Also I can see lot of properties defined as class in this Ontology. I need to understand if I am wrong here or this is the right way to define Ontology. Interesting fact is that I don't see any "Data Property" in this Ontology.
Another example which is a class and I feel it should be "Data Property": "contact name"