Methods Inf Med 2017; 56(03): 200-208
DOI: 10.3414/ME16-01-0085
Paper
Schattauer GmbH

Relating Complexity and Error Rates of Ontology Concepts

More Complex NCIt Concepts Have More Errors
Hua Min
1   Department of Health Administration and Policy, College of Health and Human Services, George Mason University, Fairfax, VA, USA
,
Ling Zheng
2   Department of Computer Science, New Jersey Institute of Technology, Newark, NJ, USA
,
Yehoshua Perl
2   Department of Computer Science, New Jersey Institute of Technology, Newark, NJ, USA
,
Michael Halper
3   Information Technology Department, New Jersey Institute of Technology, Newark, NJ, USA
,
Sherri de Coronado
4   National Cancer Institute, Center for Biomedical Informatics & Information Technology, National Institutes of Health, Rockville, MD, USA
,
Christopher Ochs
2   Department of Computer Science, New Jersey Institute of Technology, Newark, NJ, USA
› Author Affiliations

Funding Research reported in this publication was partially supported by the National Cancer Institute of the National Institutes of Health under Award Number R01CA190779. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Further Information

Publication History

received: 13 July 2016

accepted in revised form: 19 January 2017

Publication Date:
24 January 2018 (online)

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Summary

Objectives: Ontologies are knowledge structures that lend support to many health-information systems. A study is carried out to assess the quality of ontological concepts based on a measure of their complexity. The results show a relation between complexity of concepts and error rates of concepts.

Methods: A measure of lateral complexity defined as the number of exhibited role types is used to distinguish between more complex and simpler concepts. Using a framework called an area taxonomy, a kind of abstraction network that summarizes the structural organization of an ontology, concepts are divided into two groups along these lines. Various concepts from each group are then subjected to a two-phase QA analysis to uncover and verify errors and inconsistencies in their modeling. A hierarchy of the National Cancer Institute thesaurus (NCIt) is used as our test- bed. A hypothesis pertaining to the expected error rates of the complex and simple concepts is tested.

Results: Our study was done on the NCIt’s Biological Process hierarchy. Various errors, including missing roles, incorrect role targets, and incorrectly assigned roles, were discovered and verified in the two phases of our QA analysis. The overall findings confirmed our hypothesis by showing a statistically significant difference between the amounts of errors exhibited by more laterally complex concepts vis-à-vis simpler concepts.

Conclusions: QA is an essential part of any ontology’s maintenance regimen. In this paper, we reported on the results of a QA study targeting two groups of ontology concepts distinguished by their level of complexity, defined in terms of the number of exhibited role types. The study was carried out on a major component of an important ontology, the NCIt. The findings suggest that more complex concepts tend to have a higher error rate than simpler concepts. These findings can be utilized to guide ongoing efforts in ontology QA.