A learning object is any piece of information that can be used to contribute to a learning experience. The IEEE Learning Technology Standards Committee defines learning objects as “…any entity, digital or non-digital, which can be used, re-used or referenced during technology supported learning.” (2001). Learning objects can take many formats including instructional videos, websites, textbooks, illustrations from textbooks, or audio clips. They can be any size; for example a full course and a single graphic could both be described as learning objects. The format and size of a learning object depends on the need the object was created to meet, including its potential for reuse. The value of learning objects is in their reuse.
To implement a structured content development model, the underlying structure for all text learning objects must be designed. The learning objects themselves are authored in accordance to this defined structure using a markup language such as SGML (Standard Generalized Markup Language) or XML (eXtensible Markup Language). Authored content in the form of SGML/XML files resides in a content repository, which has capabilities for search, retrieval, revision, and version control, among other things. Acquisition and administration of such a repository is required. For output, the SGML/XML file must be transformed for a specified media. The transformation process requires a programmer to develop custom scripts, a technician to run the scripts once developed, and visual designers to create the look of the output media such as web pages, print products, and CD-ROMs…Developing educational content using a structured content development model requires a great deal of effort. For organizations that create a lot of similar content, the effort is worthwhile as content can be output in a variety of media, with a consistent look within each output media. Also, the concept of content that can be reused in different contexts, both within and outside an institution, is the underlying theme behind the “economics” of learning objects (Downes, 2000).
With the evolution of desktop publishing, there has been much emphasis on the look of a document. Writers not only write content, but also spend hours formatting so it has a pleasing look. More sophisticated users set up style sheets in their word processing or desktop publishing software in order to apply consistent styles throughout their documents. Usually these styles have names like body text, heading, and subhead . This naming reflects the style applied to the content, not what the content is. For example, body list may be applied to a list of learning outcomes and a list of required resources for a lesson. It may be visually attractive to style these two items in the same way, however, semantically they are very different.
Using a markup language to define the content, the learning outcomes may be identified with a tag called learningoutcomes and the resources with a tag called resources. In output to the specified medium, the content in learningoutcomes and resources could have the same style applied to them, or different styles. The power of identifying content for what it is lies in the ability to intelligently search content for reuse.