Identifiers for learning objects - a discussion paper
This paper attempts to put forward a set of requirements for the identification of learning objects. This is a discussion paper, so comments are welcome - send them to the firstname.lastname@example.org mailing list. The intention is to develop a set of learning object identifier requirements that can be used to determine which of the current technologies (URI, URN, URL, PURL, Handle, DOI, POI ...) are best suited to the needs of the UK higher and further education community.
The need for unique and persistent identifiers can be summed up as follows:
Unique and persistent identifiers are needed in order that, having discovered a resource, people can reliably cite it without having to perform the discovery again, and can pass the citation on for use by others. Similarly, software applications use identifiers to relibably reference resources, to share those references with other applications and to instantiate linkages between resources (for example, between a metadata record and the resource it describes). Often, though not always, there is a related requirement that people and software can use the identifier as a mechanism for accessing the resource, i.e. that there is a service that 'resolves' the identifier to the current location of the resource.
It should be remembered that, in the context of e-learning systems, identifiers need to be assigned to both learning objects and metadata records about those learning objects, i.e. learning objects and metadata records need to be treated as different 'resources'. There is no obvious requirement that the same kind of identifiers need to be assigned to both objects and metadata, therefore the requirements for the two kinds of identifiers are treated separately below.
As indicated above, in the context of this discussion paper, the simple answer to the question "What do we want to identify?" is:
We do not need to try and answer the question "What is a learning object?" here. However, it is worth noting the difference between a 'work' (the abstract entity representing a "distinct intellectual or artistic creation"), an 'expression' (the "intellectual or artistic realization of a work") and a 'manifestation' (the "physical [or digital] embodiment of an expression of a work"). While it is not necessary to dwell on these definitions here - interested parties should read the IFLA report on the Functional Requirements for Bibliographic Records - it is worth considering which of these we want to identify.There are some scenarios in which it is necessary to identify the 'work', for example when making general recommendations about software packages...
" Crystal Studio is a recommended resource for the teaching of crystallography at undergraduate level."
However, in the main, it is more common to need to cite a particular 'manifestation' (of an 'expression') of the 'work' (i.e. pointing a student to a particular release or language version of a learning object)..."
"To perform this exercise you will need a copy of Crystal Studio version 5.0 (versions 4.0 Lite and 4.0 Professional do not support the required options)."
Therefore, I would suggest that identifiers are assigned to each manifestation of a learning object, which in practice means that each new combination of release, language translation and platform version of a learning object should be assigned a separate identifier.
The following list forms a proposed statement of requirements for the identifiers of learning objects within the UK HE and FE community. Learning object identifiers should be:
The requirements for identifiers of metadata records about learning objects are the same as those listed above. However, it could be argued that requirements 4 and 8 (usable in Web-browsers and in non-digital environments) are of much lower priority in the case of identifiers for metadata records.
Various issues are raised by the use of persistent identifiers in practice. From the point of view of learning object creators, learning object repository administrators, resolver systems administrators and end-users, we need to be able to answer the following questions for any chosen learning object identifier scheme...
Learning object repository administrators:
Resolver systems administrators:
[distributed systems] [UKOLN]