# Ontology Metrics

The ontology metrics view displays entity and axiom counts for the axioms in the active ontology and its imports closure. Descriptions (and where appropriate links to the W3C documentation) are listed below.

For the different types of axiom metrics in this view, for example, `SubClassOf`

, right clicking (or pressing Cmd and clicking on a Mac) will display a popup menu which can be used to show the axioms in question.

**Axioms**- the combined logical and non-logical axiom count**Logical axioms**- the number of logical axioms**Declaration axioms count**- the number of declaration axioms. Declaration axioms are added under the hood in Protégé and cannot be seen in the user interface.**Class|Data Property|Data Property|Individual count**- the number of classes, object propeeties, data properties and individuals in the signature of the imports closure of the active ontology. In other words, the number of distinct classes, object properties, data properties and individuals that are mentioned in the ontology. The numbers here include built in entities, such as`owl:Thing`

if they are explicitly mentioned in the ontology. For example, an ontology that contains the single axiom`SubClassOf(A owl:Thing)`

will have a class count of 2.**DL Expressivity**- the Description Logic expressivity of the ontology. This is the name of the Description Logic that the ontology uses. It depends upon the kinds of axioms in the ontology and the kinds of class expressions used in the ontology. The maximum expressivity of an OWL 2 (DL) ontology is SROIQ(D). The maximum expressivity of an OWL 1 ontology is SHOIN(D).

## Class Axioms

**SubClassOf**- the number of SubClassOf axioms in the ontology and its imports closure.**EquivalentClasses**- the number of EquivalentClasses axioms in the ontology and its imports closure.**DisjointClasses**- the number of of DisjointClasses axiom in the ontology and its imports closure.**GCI Count**- the number of GCIs, or General Concept Inclusion axioms in the ontology an its imports closure. Protégé regards a GCI as being a SubClassOf axiom whose subclass (left hand side) is a complex class expression.**Hidden GCI Count**- A hidden GCI is a pair of axioms, one an EquivalentClasses axiom and the other a SubClassOf axiom of the form EquivalentClass(A C) and SubClassOf(A D), where C and D are complex class expressions.

## Object Property axioms

**SubObjectPropertyOf**- the number of SubObjectPropertyOf axioms in the ontology and its imports closure.**EquivalentObjectProperties**- the number of EquivalentObjectProperties axioms in the ontology at its imports closure.**InverseObjectProperties**- the number of InverseObjectProperties axioms in the ontology and its imports closure.**DisjointObjectProperties**- the number of DisjointObjectProperties axioms in the ontology and its imports closure.**FunctionalObjectProperty**- the number of FunctionalObjectProperty axioms in the ontology and its imports closure.**InverseFunctionalObjectProperty**- the number of InverseFunctionalObjectProperty axioms in the ontology and its imports closure.**TransitiveObjectProperty**- the number of TransitiveObjectProperty axioms in the ontology and its imports closure.**SymmetricsObjectProperty**- the number of SymmetricsObjectProperty axioms in the ontology and its imports closure.**AsymmetricObjectProperty**- the number of AsymmetricObjectProperty axioms in the ontology and its imports closure.**ReflexiveObjectProperty**- the number of ReflexiveObjectProperty axioms in the ontology and its imports closure.**IrreflexiveObjectProperty**- the number of IrreflexiveObjectProperty axioms in the ontology and its imports closure.**ObjectPropertyDomain**- the number of ObjectPropertyDomain axioms in the ontology and its imports closure.**ObjectPropertyRange**- the number of ObjectPropertyRange axioms in the ontology and its imports closure.**SubPropertyChainOf**- the number of SubPropertyChainOf axioms in the ontology and its imports closure.

## Data Property axioms

**SubObjectPropertyOf**- the number of SubDataPropertyOf axioms in the ontology and its imports closure.**EquivalentDataProperties**- the number of EquivalentDataProperties axioms in the ontology at its imports closure.**DisjointDataProperties**- the number of DisjointDataProperties axioms in the ontology and its imports closure.**FunctionalDataProperty**- the number of FunctionalDataProperty axioms in the ontology and its imports closure.**DataPropertyDomain**- the number of DataPropertyDomain axioms in the ontology and its imports closure.**DataPropertyRange**- the number of DataPropertyRange axioms in the ontology and its imports closure.

## Individual axioms

**ClassAssertion**- the number of ClassAssertion axioms in the ontology and its imports closure.**ObjectPropertyAssertion**- the number of ObjectPropertyAssertion axioms in the ontology and its imports closure.**DataPropertyAssertion**- the number of DataPropertyAssertion axioms in the ontology and its imports closure.**NegativeObjectPropertyAssertion**- the number of NegativeObjectPropertyAssertion axioms in the ontology and its imports closure.**NegativeDataPropertyAssertion**- the number of NegativeDataPropertyAssertion axioms in the ontology and its imports closure.**SameIndividual**- the number of SameIndividual axioms in the ontology and its imports closure.**DifferentIndividuals**- the number of DifferentIndividuals axioms in the ontology and its imports closure.

## Annotation axioms

**AnnotationAssertion**- the number of AnnotationAssertion axioms in the ontology and its imports closure.**SubAnnotationPropertyOf**- the number of SubAnnotationPropertyOf axioms in the ontology and its imports closure.**AnnotationPropertyDomain**- the number of AnnotationPropertyDomain axioms in the ontology and its imports closure.**AnnotationPropertyRange**- the number of AnnotationPropertyRange axioms in the ontology and its imports closure.