I was looking for this last month (there may even be a thread in the 
archives from me on it); I didn't anything very suitalbe.

The only potentially useful thing I found, is that id.loc.gov does 
include mappings for _some but not all_ LCSH authority records. I think 
these mappings were included in the original LCSH authority records, 
they are not value added by id.loc.gov. So any source of LCSH authority 
records would also have this info.

For example, look under "LC Classification" at 
http://id.loc.gov/authorities/subjects/sh85004812.html

I think some LCSH authority records may have more than one suggested LCC 
too (which is reasonable and makes sense).

You can look up records id.loc.gov by known term by doing, say: 
http://id.loc.gov/authorities/subjects/label/anarchism

A pre-coordinated LCSH string in a MARC record may not exactly 
correspond to an authority record, so you may have trouble matching 
there, have to figure out which part of the LCSH string matches the auth 
record.  And then, not every LCSH auth record has suggested 
corresponding LCSH, only some of them do.

But that's pretty much the only thing i was able to find when I looked 
last month.

In theory, I think a prommissing approach would be to take an existing 
corpus of bib records, and assemble statistical correlations between 
LCSH and LCC.  For instance, of all the records with a certain LCSH 
assigned, maybe there are 12 LCC's represented, and some more than 
others. This would give you some pretty likely candidates for 
appropriate LCC's for a given LCSH.  It would take some algorithmic 
tweaking probably.  It would work best on a huge corpus like OCLC or LC 
(and I think I recall a non-free product that does exactly this), but 
could possibly bear fruit on a reasonably large corpus like an 
individual research library too. It would be an interesting project for 
someone to undertake, if it resulted in open data on LCSH->LCC 
correspondences, it would be useful to many.

Jonathan

On 12/10/13 8:18 AM, Irina Arndt wrote:
> Hi CODE4LIB,
>
> we would like to add DDC classes to a bunch of MARC records, which contains only LoC Subject Headings.
> Does anybody know, if a mapping between LCSH and DDC is anywhere existent (and available)?
>
> I understood, that WebDewey http://www.oclc.org/dewey/versions/webdewey.en.html  might provide such a service, but
>
> ·         we are no OCLC customers or subscribers to WebDewey
>
> ·         even if we were, I'm not sure, if the service matches our needs
>
> I'm thinking of a tool, where I can upload my list of subject headings and get back a list, where the matching Dewey classes have been added (but a 'simple' csv file with LCSH terms and DDC classes would be helpful as well- I am fully aware, that neither LCSH nor DDC are simple at all...) . Naïve idea...?
>
> Thanks for any clues,
> Irina
>
>
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>
> Irina Arndt
> Max Planck Digital Library (MPDL)
> Library System Coordinator
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>
> Tel. +49 89 38602-254
> Fax +49 89 38602-290
>
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>
>