Zens, B. & Baumgartner, P., 2008. Making efficient use of open educational resources using a multi-layer metadata approach. In World Conference on Educational Multimedia, Hypermedia and Telecommunications. ED-Media 2008. Chesapeake, VA, pp. 585–588.
Repositories of educational content enable a worldwide exchange of learning resources and support an economic use of existing materials. Metadata provide information describing objects and are essential for the exchange and re-use of content. Due to a rapidly growing amount of content, the scalability of metadata creation is becoming an important issue. The creation of structured metadata by experts is cost-intensive and does not scale. In contrast, automatically generated metadata are cheap to obtain, but provide only limited information on the information content of objects. A third way of enriching objects with metadata is social tagging, resulting in folksonomies, i.e., collaboratively user-generated, unstructured vocabularies. Combining these three approaches can provide for a cost-effective way of enriching content with useful types of metadata allowing users to find resources that fit their needs. This approach is pursued in the MELT project, funded by the European Commission. Its (cost-)effectiveness is currently being evaluated.