If this were an electronic resource available on CD-ROM then the Carrier Type would be described as a
“computer disc.” Or, for the print version the Media Type would be “unmediated”21 and the Carrier
Type would be “volume.”
Another significant change is the discontinuation of the so-called “rule of three.” In AACR this
rule came into play when a statement of responsibility named more than three persons or corporate
bodies. The cataloguer was instructed to use only the first named author followed by the “mark of
omission” and adding “et al.” in square brackets (AACR2 1.1F5). This is no longer a part of RDA,
although it may still be used optionally by replacing “et al.” with 'and others' (RDA 2.4.1.5). One of
the goals of RDA is to facilitate the use of data from other sources such as publisher data, or metadata
that might be embedded as part of an electronic resource. Therefore RDA wants to use this data as it is,
as it appears on the resource, as it is transcribed (RDA 1.7). Data can therefore be collected without the
need for human intervention, leaving cataloguers free to do what they do best: subject analysis of the
intellectual content.