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Recommender Systems for Group Consumption of Hedonic Media Products: Theoretic Modelling, System Development and Quality Testing.


The goal of the project is to significantly improve recommender systems by means of three conjoint approaches:
  • Consideration of group consumption: Although hedonic media products are often consumed in groups, existing recommender systems implicate the isolated consumption by a single person. In contrast, our system also takes the group consumption into account.
  • Consumerism theoretic foundation: Existing recommender system approaches are based on pure informatics criteria and neglect the user behaviour. Our aim is to deepen consumption research in the area of group behaviour—that yet only exists in attempts—in order to develop a consumerism theoretic model of group consumption of hedonic media products.
  • Usability-Perspective: Although the relevance of electronic recommendations is substantially determined by the interaction- and user interface design, the current marketing and informatics research is almost exclusively focussed on the algorithms that are the base for the generation of recommendations and neglects the usability perspective. We therefore develop innovative group interactions models for negotiating compromises in groups and prototypical implement these models for a user evaluation.

This research project develops a novel Web-based recommender system, which—by means of mathematical algorithms—analyses hitherto product ratings to automatically generate individualised recommendations for consumers in order to support the selection of hedonic media products like feature films, and so becomes an important aid for decision-making.


The project DFG_Reco develops—in cooperation with all participating partners—innovative concepts and systems to support groups of users with personalised recommendations of choices to make that facilitate decision-making. The CML contributes to the DFG_Reco project with a domain-specific process model, which departs from a thorough literature review and user studies. It facilitates easy interaction among the group members and with group recommender systems. Our work concentrates on the interaction- and user interface design, which employs admitted design procedures (e.g., design principles specified in ISO 13407) of the field of Human-Computer Interaction and Computer-Supported Cooperative Work. The complexity of group recommender systems requires a sophisticated iterative development process including multiple detailed low- and high-fidelity prototyping cycles and user studies.


  • Literature review of existing group recommender systems and approaches, as well as elaboration of a domain-specific process model
  • Low-fidelity and high-fidelity prototyping with concluding user studies
  • Implementation of a Web-based and mobile group recommender system, as well as a desktop tool for evaluators of group recommender systems
  • Documentation and publication of the insights and requirements for new models, concepts, and applications for group recommender systems

Current State and Results

The project DFG_Reco has performed a thorough literature review. The review revealed building blocks of group recommender systems and commonly known approaches like list-merging strategies for joining individual predictions to group recommendations. We aligned the user interaction- and interface design according to the domain-specific process model. In the first prototyping cycle, we created low- and high-fidelity prototypes that support ad-hoc groups in a mobile scenario. We built a distributed group recommender platform, which leverages on advanced concepts for group recommendation merging strategy exploration, performance optimisation, session persistence and mobility, as well as open interfaces. We implemented and tested a Web-based mobile group recommender application along the process model. The first prototyping cycle concluded with an evaluation in terms of expert interviews and user studies. The conducted user study revealed insights about the process model, the interaction design as well as the need for evaluator tools of group recommender studies.

In the second prototyping cycle we have conducted a low-fidelity prototyping with a concluding user study. We are currently finalising the high-fidelity prototyping and implementing a mobile group recommender system as an iPhone application.


Thorsten Hennig-Thurau, Department of Marketing and Media Research, University of Muenster, Germany
moviepliot GmbH, Berlin, Germany


Tom Gross, Principle Investigator
Christoph Beckmann, Researcher
Maximilian Schirmer, Researcher

Christoph Halang, Research Assistant


The project is partly funded by the Deutsche Forschungsgemeinschaft (German Research Foundation) and will be realised in cooperation with the chair of marketing and media research of the Bauhaus-University in Weimar. The funding period is Feb. 2009 to Feb. 2011.

Further Information

Gross, T., Beckmann, C. and Schirmer, M. GroupRecoPF: A Distributed Platform for Innovative Group Recommendations. In Proceedings of the Nineteenth Euromicro Conference on Parallel, Distributed, and Network-Based Processing - PDP 2011 (Feb. 9-11, Ayia Napa, Cyprus). IEEE Computer Society Press, Los Alamitos, (accepted).

Beckmann, C. and Gross, T. Towards a Group Recommender Process Model for ad-hoc Groups and On-Demand Recommendations. In Proceedings of the 2010 International ACM Conference on Supporting Group Work - Group 2010 (Nov. 7-10, Sanibel Island, FL). ACM, N.Y., 2010. pp. 329-330. (ISBN: 978-1-4503-0387-3). ( .pdf, 549k).

Beckmann, C. and Gross, T. Leichtgewichtige Auswahlentscheidungen fuer Gruppen am Beispiel eines Recommender-Systems fuer Filme (Light-Weight Selection Decisions in Group Expemplified in a Recommender-System for Movies; in German). In Workshop-Proceedings der Tagung Mensch & Computer 2009 - 9. Fachuebergreifende Konferenz - Grenzenlos frei!? (Workshop-Proceedings of the Mensch & Computer Conference; in German)- M&C 2009 (Sept. 6-9, Berlin, Germany). Logos Verlag, Berlin, 2009. pp. 213. (ISBN: 978-3-8325-2181-3).

Created by: mirko.fetter last modification: Friday 28 of January, 2011 [17:55:22 UTC] by tom.gross