- - - - - - - - - -
view on github
getting started
common errors
chaining commands
global options
- - - - - - - - - -
- - - - - - - - - -
ROBOT is licensed under the
BSD 3-Clause License.
Theme by orderedlist



  1. Overview
  2. Types of metrics
  3. Output formats


ROBOT can compute a number of metrics about your ontology, such as entity and axiom counts, qualitative information such as OWL 2 profiles and more complex metrics aimed at informing ontology developers such as logical expressivity and axiom shape. A number of essential metrics can be generated very simply as follows:

robot measure --input uberon_fragment.owl --output results/metrics.tsv

This will generate a table with metrics such as:

Types of metrics

There are three general modes for computing metrics:

  1. Essential metrics (--metrics essential, default)
  2. Extended metrics (--metrics extended)
  3. All metrics (--metrics all)
  4. Reasoner metrics (--metrics all-reasoner, --metrics essential-reasoner, --metrics extended-reasoner)

Essential metrics include basic ontology entity counts (number of classes, individuals and properties), axiom counts and a few qualitiative metrics such as OWL profiles, see the initial example above.

robot measure --input uberon_fragment.owl --format json --metrics essential --output results/metrics_essential.json

Extended metrics contain all the essential metrics, and additional details on axiom types, logical expressivity and datatypes. Use: --metrics extended.

All metrics include all the essential and extended metrics, as well as a range of more complex metrics targeted at OWL and reasoning specialists, such as information about GCIs, shape of the class hierarchy and potential cyclicity. Use: --metrics all.

Reasoner metrics (currently only satisfiability status and number of unsatisfiable classes) can be collected by appending -reasoner to the --metrics parameter, for example: --metrics essential-reasoner.

robot measure --input uberon_fragment.owl --format json --metrics essential-reasoner --output results/metrics_essential_reasoner.json

A full breakdown of all metrics can be found in the table below. In the actual output, you will also see the same metrics ending with _incl. This indicates that the metric is the ontology including its imports. Otherwise, the metric is just representative of the ontology without imports.

Some abbreviations useful to understand the following:

metric metric_value metric_type explanation
abox_axiom_count 0 single_value Number of axioms in the ABox
annotation_property_count 24 single_value Number of annotation properties
assert_n_subclass_avg 1.0 single_value Average number of (asserted) subclasses per class
assert_n_superclass_avg 1.0416666666666667 single_value Average number of (asserted) superclasses per class
ax_complexrhs_count 15 single_value Number of axioms with a complex right hand side
axiom_count 703 single_value Number of axioms
axiom_length_max 4 single_value Longest axiom in terms of number of entities used (including duplicate uses).
axiom_type_count SubClassOf 37 map_value Number of axioms of a specific type, such as SubClassOf
axiom_types AnnotationAssertion list_value Indicates the presence of an axiom type in the ontology.
certain_cycle false single_value If true, there is a definite cycle in the ontology. If false, cyclicity is unknown (experimental).
class_count 24 single_value Number of classes in the ontology
class_sgl_subcl_count 10 single_value Number of super-classes which have more than one subclass.
constructs AL list_value Logical constructs used
dataproperty_count 0 single_value Number of distinct data properties.
datatypes_builtin XSD_BOOLEAN list_value Datatypes used from the built-in datatype map (like XSD schema datatypes).
datatypes_count 2 single_value Total number of distinct datatypes.
dt_builtin_count 2 single_value Total number of distinct built-in datatypes.
dt_notbuiltin_count 0 single_value Total number of distinct custom (not built-in) datatypes.
expressivity ALEH+ single_value Logical expressivity.
gci_count 0 single_value Total count of GCI axioms.
gci_hidden_count 2 single_value Total count of hidden GCIs.
individual_count 0 single_value Number of individuals.
instance_per_class_avg 0.0 single_value Average number of individuals per class.
namespace_axiom_count 17 map_value Number of axioms using at least one term in a namespace.
namespace_entity_count 17 map_value Number of distinct entities used from a namespace.
logical_axiom_count 41 single_value Number of logical axioms in ontology
most_freq_concept UBERON:0000475 single_value Most frequently used class.
multiple_inheritance_count 2 single_value Number of classes with multiple inheritance.
named_supercl_count_max 1 single_value Maximum number of named superclasses.
obj_property_count 2 single_value Number of object properties.
ontology_anno_count 0 single_value Number of ontology annotations.
ontology_id single_value The ontology id.
owl2_dl false single_value Does the ontology correspond to the OWL2 DL profile?
owl2_el false single_value Does the ontology correspond to the OWL2 EL profile?
owl2_ql false single_value Does the ontology correspond to the OWL2 QL profile?
owl2_rl false single_value Does the ontology correspond to the OWL2 RL profile?
owl2 true single_value Does the ontology correspond to the OWL2 Full profile?
owl2dl_profile_violation UseOfUndeclaredAnnotationProperty 531 map_value Counts of OWL2 DL profile violations.
rbox_axiom_count 2 single_value How many axioms in the RBOX?
rdfs false single_value Does the ontology correspond to the RDFS profile?
rule_count 0 single_value Number of SWRL rules used.
signature_entity_count 52 single_value Total number of entities in signature, including classes and individuals.
syntax RDF/XML Syntax single_value What serialisation is used for the ontology?
tautology_count 0 single_value Number of tautological axioms.
tbox_axiom_count 39 single_value Number of TBOX axioms (without RBOX).
tbox_nominals false single_value Number of TBOX axioms with nominals.
tboxrbox_axiom_count 41 single_value Number of TBOX axioms (with RBOX).
undecl_entity_count 17 single_value Number of undeclared entities.

Output formats

Currently, the following serialisation formats are supported:

To serialise the metrics as json, for example, we run:

robot measure --input uberon_fragment.owl --format json --metrics all --output results/metrics_all.json

Note that if no --format/-f is explicitly provided, ROBOT will try to infer the inteded format from the file extension instead. Failing that, it will generate a TSV file.

Error Messages

Metrics format error

Only the following --format/-f options are currently supported: tsv, csv, json, yaml, html.

Metrics type error

Only the following --metrics/-m options are currently supported: essential, essential-reasoner, extended, extended-reasoner, all, all-reasoner.