Factors Affecting Reusability
Reusability of digital learning resources can mean reuse with or without modification. It can also mean different things for different types of resources, as is illustrated by some examples:
- A college professor selects a text book for a class. She may anticipate using all of it, parts of it or just the exercises. She does not anticipate being able to copy portions of the book and publish them in another book because that would violate copyright.
- A keynote speaker prepares to give the third version of the same talk. He may start with a PowerPoint™ presentation and intend to use almost all of its content, altering some presentation elements (such as the opening slide, the footer and the date) and updating a few slides.
- A student selects a JPEG from a library of scanned astronomical images. She will most likely paste it into a report as is. Alterations would likely ruin the image.
- A mathematician writes an applet that allows students to alter some parameters in a differential equation and view the resulting level curves. This applet may be shown in class during a lecture, used as part of a lab, provided as supplementary material, or incorporated into an online quiz. It might also be appropriate for several different courses (not just in mathematics) but may require a particular version of a Java™ virtual machine or a viewer for a particular computer algebra system. The license associated with the applet may restrict certain types of reuse (e.g. commercial).
These examples make it clear that there are multiple dimensions to reusability. For the purposes of the framework presented here, five factors are identified:
These represent a distillation and unification of reusability from the perspectives of learning theorists, instructional designers, technology designers, content developers, standards developers, digital librarians and policy makers.
Each of these factors plays a different role. The granularity of a digital learning resource determines what is meant by “reuse” and frames any discussion of reusability. The design of a resource, which includes instructional and structural design, determines its suitability for adoption† and adaptation† as well as its usability from the perspective of different learners. Interoperability affects the degree to which a resource will actually work, rights affect its permitted uses and metadata affects the ability of a resource to be discovered by someone wishing to reuse† it.