Although I acknowledge Roy's points and agree with them. I do think the 
 research on identifying what MARC fields and subfields have been used is 
 necessary and beneficial for going forward, but I think the normative 
 question of what data is useful is more interesting and important. Let 
 me give a few examples of why I think this besides just format-specific 

 Some fields that show up a lot don't seem very useful. In my opinion, 
 one of these is the 530 note, which says things like "Also available 
 online" or "Also available on videocassette." If the other version is 
 already in the catalog being searched, hopefully it should have already 
 come up in whatever search was done. In the more likely case that it's 
 not in the local catalog being searched, it confuses users, who often 
 interpret the note to mean the other version is available to them. 
 Presumably a system that did a better job of incorporating FRBR 
 relationships would make this note obsolete anyway.

 On the other hand, there are some things that I think ought to be in 
 MARC that aren't. I have devoted a lot of effort to trying to get some 
 of these that are related moving image materials added. One that still 
 isn't there is a consistent, machine-actionable place to unambiguously 
 record the date of original release of a moving image in the 
 bibliographic record. Original release date is generally given in 
 citations for movies and TV programs so it's clear that it's important 
 to users.

 Use can be unreliable for other reasons. For example, there is a 
 chicken and egg problem with many data elements. Some of these are old 
 elements which were prescient, but not used by systems. This led many 
 catalogers to stop bothering with these fields despite their potential 
 usefulness. As a former colleague put it, "I got tired of cataloging for 
 my grandchildren." At my former library, we came up with a way to allow 
 users to search for chamber music by instrumentation 
 (, but we 
 had long ago stopped populating the 048 coded instrumentation fields 
 that we needed to drive the searches. This left us with a lot of work to 
 fill in the missing gaps in the data.

 A lot of newer fields and subfields don't seem to get a lot of use. 
 It's partially because they are often niche elements, but it's also that 
 they tend not to be supported by systems so they're not searchable in 
 useful ways and they're often not publicized enough so that the broader 
 community of catalogers know about them. This isn't necessarily a 
 reflection of their potential value.

 Although application profiles may be a good solution for specialized 
 data, there have to be the time and resources to set them up and 
 maintain them. For smaller special interest groups, this may be 
 difficult or impossible. As the OLAC liaison to CC:DA, I feel 
 overwhelmed by the number of changes that we would like to see in the 
 way moving images and other media materials are handled in RDA. OLAC is 
 struggling with tackling this as well as creating best practice 
 guidelines for RDA. It's hard for me to see that we have the resources 
 for a major project on another front, such as an application profile for 
 a new bibliographic framework.


 Kelley McGrath
 University of Oregon
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