The ontology service 110 can also generate and/or maintain interface fulfillment maps 140. In some examples, an interface fulfillment nap 140 may also be referred to as a context collection implementation. An interface fulfillment map 140 can be provided in the ontology service 110 for individual pairs of context collection formats 136 and context collection interfaces 138. An interface fulfillment map 140 associated with a particular context collection format 136 and a particular context collection interface 138 can indicate how event data 122, formatted according to the particular context collection format 136, satisfies the particular context collection interface 138. Accordingly, event data 122 formatted according to a particular context collection format 136 may satisfy a particular context collection interface 138 if the event data 122 includes the data elements specified by the ontological definition 134 of the particular context collection interface 138, and if an interface fulfillment map 140 exists at the ontology service 110 that is associated with both the particular context collection format 136 and the particular context collection interface 138.