Given that we want to ensure the stability of our ontology, the task is to use the data that we have, and apply it onto the ontology. This means that if we take a particular field or data point, we should be able to understand how it fits into the ontology.
Visualize the ontology (see Michal's comment here), and make sure that everything makes sense, as far as you can see.
Take individual data points and try to place them in the ontology. If the ontology does not make sense, then this small test should be able to show us that the ontology is either incomplete, or is incorrect/inconsistent (to a certain extent)
Given that we want to ensure the stability of our ontology, the task is to use the data that we have, and apply it onto the ontology. This means that if we take a particular field or data point, we should be able to understand how it fits into the ontology.