Artificial Intelligence Review

, Volume 24, Issue 2, pp 179–197 | Cite as

Explanation in Recommender Systems



There is increasing awareness in recommender systems research of the need to make the recommendation process more transparent to users. Following a brief review of existing approaches to explanation in recommender systems, we focus in this paper on a case-based reasoning (CBR) approach to product recommendation that offers important benefits in terms of the ease with which the recommendation process can be explained and the system’s recommendations can be justified. For example, recommendations based on incomplete queries can be justified on the grounds that the user’s preferences with respect to attributes not mentioned in her query cannot affect the outcome. We also show how the relevance of any question the user is asked can be explained in terms of its ability to discriminate between competing cases, thus giving users a unique insight into the recommendation process.


attribute-selection strategy case-based reasoning explanation recommender systems 


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  1. Aha, D.W., Breslow, L.A., Muñoz-Avila, H. 2001Conversational Case-Based ReasoningApplied Intelligence14932CrossRefGoogle Scholar
  2. Armengol, E., Palaudàries, A., Plaza, E. 2001Individual Prognosis of Diabetes Long-Term Risks: a CBR ApproachMethods of Information in Medicine404651PubMedGoogle Scholar
  3. Burke, R. 2002Interactive Critiquing for Catalog Navigation in E-CommerceArtificial Intelligence Review18245267CrossRefGoogle Scholar
  4. Doyle, M., Cunningham, P. 2000

    A Dynamic Approach to Reducing Dialog in On-Line Decision Guides

    Blanzieri, E.Portinale, L. eds. Advances in Case-Based ReasoningSpringer-VerlagBerlin Heidelberg4960
    Google Scholar
  5. Elstein, A.S., Schulman, L.A., Sprafka, S.A. 1978Medical Problem Solving: an Analysis of Clinical ReasoningHarvard University PressCambridge, MAGoogle Scholar
  6. Evans-Romaine, K., Marling, C. (2003). Prescribing Exercise Regimens for Cardiac and Pulmonary Disease Patients with CBR. In McGinty, L. (ed.) ICCBR-03 Workshop Proceedings, 45–52. Technical Report 4/2004, Department of Computer and Information Science, Norwegian University of Science and TechnologyGoogle Scholar
  7. Gaasterland, T., Godfrey, P., Minker, J. 1992An Overview of Cooperative AnsweringJournal of Intelligent Information Systems1123157CrossRefGoogle Scholar
  8. Hammond, K.J., Burke, R., Schmitt, K. 1996

    A Case-Based Approach to Knowledge Navigation

    Leake, D.B. eds. Case-Based Reasoning: Experiences, Lessons., Future DirectionsAAAI PressMenlo Park, CA125136
    Google Scholar
  9. Herlocker, J. L., Konstan, J. A., Riedl, J. (2000). Explaining Collaborative Filtering Recommendations. In Proceedings of the 2000 ACM Conference on Computer Supported Cooperative Work, 241–250. ACM Press: New York, NYGoogle Scholar
  10. Kassirer, J.P., Kopelman, R.I. 1991Learning Clinical ReasoningWilliams and WilkinsBaltimore, MDGoogle Scholar
  11. Kohlmaier, A., Schmitt, S., Bergmann, R. 2001

    A Similarity-Based Approach to Attribute Selection in User-Adaptive Sales Dialogues

    Aha, D.W.Watson, I. eds. Case-Based Reasoning Research and DevelopmentSpringer-VerlagBerlin Heidelberg306320
    Google Scholar
  12. McGinty, L., Smyth, B. 2002

    Comparison-Based Recommendation

    Craw, S.Preece, A. eds. Advances in Case-Based ReasoningSpringer-VerlagBerlin Heidelberg575589
    Google Scholar
  13. McSherry, D. 1999Strategic Induction of Decision TreesKnowledge-Based Systems12269275CrossRefGoogle Scholar
  14. McSherry, D. 2001aInteractive Case-Based Reasoning in Sequential DiagnosisApplied Intelligence146576CrossRefGoogle Scholar
  15. McSherry, D. (2001b). Minimizing Dialog Length in Interactive Case-Based Reasoning. In Proceedings of the Seventeenth International Joint Conference on Artificial Intelligence, 993–998. Morgan Kaufmann: San Francisco, CA.Google Scholar
  16. McSherry, D. (2002a). Mixed-Initiative Dialogue in Case-Based Reasoning. In Aha, D.W. (ed.) Proceedings of the ECCBR-02 Workshop on Mixed-Initiative Case-Based Reasoning, 1–8. Robert Gordon University: Aberdeen.Google Scholar
  17. McSherry, D. (2002b). Recommendation Engineering. In Proceedings of the Fifteenth European Conference on Artificial Intelligence, 86–90. IOS Press: Amsterdam.Google Scholar
  18. McSherry, D. 2002cThe Inseparability Problem in Interactive Case-based ReasoningKnowledge-Based Systems15293300CrossRefGoogle Scholar
  19. McSherry, D. (2003a). Increasing Dialogue Efficiency in Case-Based Reasoning Without Loss of Solution Quality. In Proceedings of the Eighteenth International Joint Conference on Artificial Intelligence, 121–126. Morgan Kaufmann: San Francisco, CA.Google Scholar
  20. McSherry, D. 2003b

    Similarity and Compromise

    Ashley, K.D.Bridge, D.G. eds. Case-Based Reasoning Research and DevelopmentSpringer-VerlagBerlin Heidelberg291305
    Google Scholar
  21. McSherry, D. 2004

    Incremental Relaxation of Unsuccessful Queries

    Funk, P.González-Calero, P. eds. Advances in Case-Based ReasoningSpringer-VerlagBerlin Heidelberg331345
    Google Scholar
  22. Reilly, J., McCarthy, K., McGinty, L., Smyth, B. (2005) Explaining Compound Critiques. Artificial Intelligence Review. This IssueGoogle Scholar
  23. Shimazu, H. 2002ExpertClerk: A Conversational Case-Based Reasoning Tool for Developing Salesclerk Agents in E-Commerce WebshopsArtificial Intelligence Review18223244CrossRefGoogle Scholar
  24. Sørmo, F., Aamodt, A. 2002

    Knowledge Communication and CBR

    González-Calero, P. eds. Proceedings of the ECCBR-02 Workshop on Case-Based Reasoning for Education and TrainingRobert Gordon UniversityAberdeen, Scotland4759
    Google Scholar
  25. Sørmo F., Cassens J., Aamodt A. (2005). Explanation in Case-Based Reasoning: Perspectives and Goals. Artificial Intelligence Review. This IssueGoogle Scholar

Copyright information

© Springer 2005

Authors and Affiliations

  1. 1.School of Computing and Information EngineeringUniversity of UlsterNorthern IrelandUK

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