The Task Force on Machine-Actionable Data Elements in RDA Chapter 3 has recently submitted a discussion paper to the ALA Committee on Cataloging: Description and Access.
The Task Force was struck to “evaluate the structure of data elements in RDA Chapter 3 that contain quantitative information.” RDA Chapter 3 deals with the descripition of the resource carrier and the Task Force was looking specifically at sections 3.4 (Extent) and 3.5 (Dimensions), also considering other related sections such as 3.16 (Sound Characteristics), 3.17 (Projection Characteristics), and 3.19 (Digital File Characteristics).
After evaluation of a number of examples they identified a common pattern and proposed a model consisting of three parts: the Aspect being measured, the Unit of measurement, and the numerical Quantity.
It’s hoped that improvements in this area, i.e. beyond just a textual statement of extent, could provide the following:
• Easier matching for the purposes of determining differing content
• Sorting by size, dimension, or other criteria
• More granular faceting for media materials based on extent
• A better path towards automated determination of extent
• Provision of textual values and labels in a variety of languages
• Ability to compress and itemize more complex extent information for particular users (similar to MARC holdings data)
• Validation of data at the time of input
The Task Force notes that, “If we are to have the data to provide the functionality above, we should start now, rather than later.” They also suggest that “… providing the information we have now in a more machine-friendly form should be no more expensive than what we do now in text, particularly with an intelligent user interface in place that supports the use of controlled vocabularies for textual elements.”
Here’s a simple example of how this might work. The current textual statement would be recorded like this in RDA:
245 pages ; 23 cm
This might appear in the proposed Aspect–Unit–Quantity model broken out into separate parts like this:
Aspect: extent/number of subunits
There’s a great diagram on page 8 of this report that is worth taking a close look at. It presents a graph of how this might be expressed as a single extent class, which is the first of 3 options proposed by the Task Force.
This discussion paper is directed at the CC:DA and its constituenices but the Task Force has asked that it be sent to the JSC for consideration at its meeting this month. Members of the Task Force include: Peter Rolla (chair); John Attig; Karen Coyle; Gordon Dunsire; Diane Hillmann; Randall Roeder; Paul Weiss; and Kathy Winzer.