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OOPS! (OntOlogy Pitfall Scanner!) helps you to detect some of the most common pitfalls appearing when developing ontologies.

To try it, enter a URI or paste an OWL document into the text field above. A list of pitfalls and the elements of your ontology where they appear will be displayed.

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Evaluation results

This results have been generated from DBpedia Ontology 3.8 on 19th March of 2014. These results might be outdated if the original ontology changes.

It is obvious that not all the pitfalls are equally important; their impact in the ontology will depend on multiple factors. For this reason, each pitfall has an importance level attached indicating how important it is. We have identified three levels:

  • Critical Critical : It is crucial to correct the pitfall. Otherwise, it could affect the ontology consistency, reasoning, applicability, etc.
  • Important Important : Though not critical for ontology function, it is important to correct this type of pitfall.
  • Minor Minor : It is not really a problem, but by correcting it we will make the ontology nicer.

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Results for P04: Creating unconnected ontology elements. 11 cases | Minor Minor

Results for P07: Merging different concepts in the same class. 3 cases | Minor Minor

Results for P08: Missing annotations. 1794 cases | Minor Minor

Results for P10: Missing disjointness [1, 2, 3]. ontology* | Important Important

Results for P11: Missing domain or range in properties. 452 cases | Important Important

Results for P12: Missing equivalent properties. 74 cases | Important Important

Results for P13: Missing inverse relationships. 852 cases | Minor Minor

Results for P20: Misusing ontology annotations. 3 cases | Minor Minor

Results for P30: Missing equivalent classes. 5 cases | Important Important

When an ontology is imported into another, classes with the same conceptual meaning that are duplicated in both ontologies should be defined as equivalent classes to benefit the interoperability between both ontologies. However, the ontology developer misses the definition of equivalent classes in the cases of duplicated concepts. An example of this pitfall can be not to have the equivalent knowledge explicitly defined between "Trainer" (class in the imported ontology) and "Coach" (class in the ontology about sports being developed).

• The following classes might be equivalent:,,,,,,

Results for P31: Defining wrong equivalent classes. 9 cases | Critical Critical

Two classes are defined as equivalent when they are not necessarily equivalent. For example, defining “Car” as equivalent to “Vehicle”

• The following classes might not be equivalent:,,,,,,,,,

Results for P34: Untyped class. 46 cases | Important Important

Results for P35: Untyped property. 30 cases | Important Important

SUGGESTION: symmetric or transitive object properties. 112 cases


  • [1] Gómez-Pérez, A. ''Ontology Evaluation''. Handbook on Ontologies. S. Staab and R. Studer Editors. Springer. International Handbooks on Information Systems. Pp: 251-274. 2004.
  • [2] Noy, N.F., McGuinness. D. L. ''Ontology development 101: A guide to creating your first ontology.'' Technical Report SMI-2001-0880, Standford Medical Informatics. 2001.
  • [3] Rector, A., Drummond, N., Horridge, M., Rogers, J., Knublauch, H., Stevens, R.,; Wang, H., Wroe, C. ''Owl pizzas: Practical experience of teaching owl-dl: Common errors and common patterns''. In Proc. of EKAW 2004, pp: 63–81. Springer. 2004.
  • [4] Hogan, A., Harth, A., Passant, A., Decker, S., Polleres, A. Weaving the Pedantic Web. Linked Data on the Web Workshop LDOW2010 at WWW2010 (2010).
  • [5] Archer, P., Goedertier, S., and Loutas, N. D7.1.3 – Study on persistent URIs, with identification of best practices and recommendations on the topic for the MSs and the EC. Deliverable. December 17, 2012.
  • [6] Heath, T., Bizer, C.: Linked data: Evolving the Web into a global data space (1st edition). Morgan & Claypool (2011).

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