Reusability is considered as an essential and undoubtedly the most important quality of learning objects (Sicilia & Garcia, 2003). A learning object is defined as follows (McGreal, 2004):
"A learning object is any reusable digital resource that is encapsulated in a lesson or assemblage of lessons grouped in units, modules, courses, and even programs. A lesson can be defined as a piece of instruction, normally including a learning purpose."
So far, there have been many attempts to support learning objects reuse, but most of these efforts have focused on defining reusable patterns (Baggetun, Rusman, & Poggi, 2004; Jones & Boyle, 2007) and on designing artifacts for evaluating and recovering materials (Cuadrado & Sicilia, 2005; Padron, Diaz, & Aedo, 2007). Therefore, in keeping with the experience in software development, effort should be put to define methods that permit the discovery of object commonalities. In turn, this information would allow for reuse.
Since reusability refers to prospective and future usage scenarios, it is difficult to manage. The concept of reusability encompasses aspects related to format, interpretation, and pedagogical suitability (Sicilia, 2004). Thus, in order to achieve effective reusability it is necessary to tackle the problem from the point of view of:
* The learning objects. The correct definition and formalization of learning objects to allow for determining their potential reuse.
* The learning contexts. The adequate specification of the learning context permits determining the appropriate instruction method and, thereby, identifying the more reusable tasks or activities.
The standards and tools previously available have focused on the first of the views presented above by dealing with aspects regarding format (but which overlooks the analysis of the specific context). In order to overcome this matter, the study of reusability in the development process of computer-supported learning systems has been proposed. A computer-supported learning system can be considered as a structured set of learning components, whose qualities and characteristics rely on the learning components that compose it. Thus, according to this notion, reusability refers to the ability to use services or learning objects for multiple courses or lessons (Hartshorne, 2003). In this context, the computer-supported learning systems reusability must take into account the features of the learning system to identify, recover, and use the learning components that comprise the system. Based on the experience of software development, reusability should be considered at the early phases of the development process (Kang, 1998). For this reason, and with the purpose of facilitating the identification of commonalities and further reuse, the definition of systematic analysis methods is needed.
The rest of the paper is organized as follows. The second section describes the motivations for a specific analysis approach in the development of computer-supported learning systems. The following sections define our analysis method and include an example on how the approach has been applied. Finally, a set of conclusions and recommendations for future work are presented.
The Motivation for a Specific Analysis Method
Courseware is defined as any instructional system delivering content via computers that supports learners as well as teachers in their educational efforts, in a technical and instructional way (Grutzner, Ruhe & Pfahl, 2002). The life-cycle of the earlier courseware development methods resembles the phases of the traditional software development process: analysis, design, development, and evaluation. As Goodyear points out, the relation between software engineering and learning resources development is particularly strong in analysis-related tasks:
"The main areas of overlap between software engineering and courseware engineering are probably to be found in those areas concerned with requirements analysis and design. …