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October 21, 2008

CEN endorses European Metadata for Learning Opportunities

It was a great week for course advertising in Europe last week as CEN (Comite Europeen de Normalisation - European Committee for Standardization) endorsed both a Workshop Agreement and a commitment to develop it into a European Norm (EN) for Metadata for Learning Opportunities (MLO). MLO defines a common model for expressing information about learning opportunities such as the courses available at a university such that they can be aggregated by other services such as advice centres, search engines, or brokerages.

An EN is a formal European Standard, whereas the CEN Workshop Agreement (CWA) agreed on 13th October represents an interim specification that can be referenced immediately by implementers while the formal standardisation process - which may take up to two years - goes ahead. Once a European Norm (EN) is agreed, it becomes a de jure standard throughout the community, replacing any similar standards in place in member states.

So what is MLO? MLO is a standard model and vocabulary that represents the common subset of several existing specifications used for advertising courses. This includes XCRI from the UK, CDM from Norway, CDM-FR from France, EMIL from Sweden, and PAS1068 from Germany. The common subset consists of four classes and 13 properties that are common to all or most of these existing specifications, plus references to other properties commonly used from Dublin Core (see below).

MLO UML diagram - download the specification below for textual description

Rather than replacing the existing specifications, MLO standardises a common model that is then implemented by specifications as a conformant binding. This means that, in practice, each specification has to be slightly modified to conform to the same common core, but retains its local extended properties and implementation architecture. So developers already using these specifications can become MLO-conformant very easily by adopting the updated version when it becomes available, which should itself be a very minor update as the standard is based on the existing commonalities. It also opens the door to other communities or consortia developing their own bindings for different applications or markets - for example using a different base technology specification such as RDF, JSON or Atom Syndication Format. Any specifications, though they may have a very different technical implementation, will still share common concepts and properties that developers can use to make transforms between them.

Why did MLO take this approach rather than standardise a binding? Well, one of the key considerations is the lifetime of standards. A standard has to stand for a much longer period of time than a specification, enough time for new technologies to come into play and become the preferred implementation approach.

Another consideration is the need for different kinds of implementations in different situations - for example, mobile applications, distributed applications, centralized systems, REST, SOAP and so on. Again, architectures also have trends that evolve over time, and can easily overtake a standard.

Finally, there is the need for communities to define their own vocabularies, extensions, and conventions. One approach to this is to define a very large standard of what is hoped to be all possible properties and classes and to then constrain this model in application profiles. Another approach is to define a common core and then allow communities to extend this common core in any way they wish. This largely maps to the difference between the approaches taken by Learning Object Metadata and Dublin Core; MLO takes the latter approach.

So what impact will MLO have? The initial impact is to some extent psychological - implementers can go ahead and commit to using specifications that are going to conform to MLO with greater confidence, as they are based on a standard that is going to be around for a long time. We will also see transforms and crosswalks becoming available between the existing course advertising specifications, and this may lead to new opportunities for services that operate across European countries such as Ploteus. As more learning opportunities are advertised in MLO-conformant formats new services that aggregate this information for different purposes become viable.

In the longer term there is a commitment from all the specification communities involved in MLO to continue to work together and seek further opportunities to adopt common models. However the preferred approach is to see what emerges as common use in implementation communities rather than to design new models from first principles.

The MLO document is still awaiting editorial comments before being prepared for formal publication by CEN; however a draft is currently also available here.

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