Towards a Global Component Architecture for Learning Objects: A Comparative Analysis of Learning Object Content Models Katrien Verbert, Erik Duval Dept. Computerwetenschappen, Katholieke Universiteit Leuven Celestijnenlaan 200A, B-3001 Heverlee, Belgium {Katrien.Verbert, Erik.Duval}@cs.kuleuven.ac.be Abstract: This paper investigates basic research issues that need to be addressed in order to reuse learning objects in a flexible way. We review a number of learning object content models that define learning objects and their components in a more or less precise way. A comparative analysis is made of these models in order to address questions about repurposing learning objects in a different context. The content models are mapped on our general model for learning objects to facilitate the comparison. 1. Introduction Learning objects are often regarded as traditional documents. We can reuse a paragraph or a sentence of a document by copy and paste in new and different documents. However, it is possible to reuse learning objects in a much more sophisticated way, if we can access the components of a learning object and repurpose them on-the-fly. However, this requires a more innovative and flexible underlying model of learning object components. In order to put such an approach into effect, some basic research issues need to be addressed (Duval & Hodgins 2003). According to the Learning Object Metadata (LOM) standard, a learning object is 'any entity, digital or non-digital, that may be used for learning, education or training' (Duval 2002). However, this definition allows for an extremely wide variety of granularities (Duval & Hodgins 2003). Learning object content models address this problem. Content models identify different kind of learning objects and their components. They provide a more precise definition of what learning objects are and allow us to identify learning object components and repurpose them. There exist a number of learning object content models, for example the SCORM Content Aggregation Model (Dodds 2001) and the CISCO RLO/RIO Model (Barrit et al. 1999). A first basic research issue concerns the comparative analysis of these models. The definition of a learning object by SCORM differs from that of CISCO. It is not clear whether a SCORM learning object or component can be repurposed within a CISCO context. To answer this question, a number of content models are investigated in this paper. Six potential learning object content models were found for inclusion in the analysis. Inclusion or exclusion was decided on the basis of whether all data, needed for the comparison, were published. The following models are included in this survey: the Learnativity content model (Wagner 2002), the Microsoft model (Elliot), the ADL academic co-lab model (Brown 2002), the SCORM content aggregation model (Dodds 2001), the CISCO RLO/RIO model (Barrit et al. 1999) and the NETg learning object model (L'Allier 1997). In the following sections, we first briefly outline each model that is included in this survey to give a general idea of the model. Then the models are compared with one another. A new, general content model is developed and existing content models are mapped to this model to facilitate a comparative analysis. Conclusions and future work conclude this paper.