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Reclassification DDC To LCC

The prime advantage of LCC for a North American library, or a library purchasing North American material, is that it is more frequently in CIP and derived MARC records than any other.

There are certainly areas which are problematic, depending of the prime subject concentration of the collection. We have customers who prefer to use with LC artistic photography NH, medicine W. Canadian history FC, Canadian literature PS 800) and/or Canadian KF or Moys. But still the bulk of material need not be classed inhouse.

The several libraries we've reclassed from DDC to LCC have been pleased with the slight rearrangement of material, the more detailed classification, and escaping DCC phoenix (redone) schedules. LC does not assign new meanings to previously used numbers, although topics are occasionally shifted.

We have done several DDC to LCC reclassifications. Here are some practices which we found to work well for patrons, and which eased the transition for staff.

1) Class all new material in LCC

On day one, class all new material in LCC. Most material will have CIP with an LCC number. Have classifiers unfamiliar with LCC look the number up in the schedules to ascertain how it was constructed.

For material which must be originally classified, check the first subject heading against an LC MARC database (we use ITS MARC English).

LCSH can also be used as an index to the classification, if the cataloguer does not know which schedule index to consult. The meanings of at least the first letters should be memorized.

Use the LC Cuttering method as opposed to Cutter-Sanborn. This table can soon become internalized, and will not have to be consulted.

2) Ribbon shelving

Shift all DDC books down on the shelves, shelving tightly. Shelve the newly classed LCC books above.

There should be a rough correspondence between subject matter above and below. There will be less walking for patrons to see both sections for most subjects. To create this correspondence shelve in this order:

000 100,200 900 300 700

400,800 500 600

There will be some lack of correspondence, e.g., recreation in 790, and the DDC 000s split between LCC's A and Z. Place labelled wooden blocks on the DDC shelves to direct patrons to moved classes. It would, w think, because too much confusion to move parts of classes such as 790s or 020s to be with their LCC counterparts.

3) Osmotic reclassification

Never reshelve a DDC book in the DDC section. After circulation, return the book to cataloguing for reclassification. It is also possible to notify cataloguing of books checked out (by sending the circulation card or shelf list for libraries having either of those) so that the reclassification is completed by the time the book is returned.

4) Initially avoid down the shelf reclassification.

With the exception of reference materials (and perhaps reserve materials in an academic library) avoid down the shelf reclassification for some time. Down the shelf reclassification would result in time being absorbed by obscure material lacking MARC records having LCC numbers, and which may never be used.

5) Weed

When the DDC collection has shrunk to one quarter or less of the total collection, undertake weeding of the DDC collection. The remainder may be reclassed leisurely.

6) Use automation

Many have found MarcEdit to be a good tool for inserting LCC numbers into legacy records.

Please feel free to ask any questions I have not covered or any points about which I have not been clear.


One of our staff members, Richard Violette, has found the use of a conversion table such as the following helpful in assigning LCC to records which have an 082 DDC but no 050 LCC.

Conversion tables : LC-Dewey, Dewey-LC / Mona L. Scott, with the assistance of Christine E. Alvey. -- Englewood, Colo. : Libraries Unlimited, 1993.

Personally, I don't favour the use of such tables myself, because the structures of the two systems are so different. A 5XX number can suggest Q, as opposed to a 6XX number suggesting T, and of course 8XX numbers can give you the nationality of the author without having to look it up. But I prefer to approach LCC by topic.

More helpful I think is a concordance of subject headings and LCC class numbers. We or the library's systems person should be able to construct one from the library's records. In the left column you have the 1st 650 from each MARC record which has an 050. In the right hand column you have each 050 associated with that first 650. The classifier would have to check the numbers against the schedule to determine which is appropriate, but such a concordance does suggest numbers, The same use can be made of LCSH, but not every heading has a number.

One can have concordances in as many languages as there are languages of subject headings. If there are OCLC records in the database, LCC numbers can also be found in 090.

I would like to stress the value of osmotic reclassification in the form of reclassing materials while on loan, printing the labels, and remarking upon return from circulation. It is a truism that weeding should be undertaken before reclassification. This is an expensive, time consuming process, and needed material could be mistakenly discarded. If all circulated materials are reclassed while on loan for, say, two years, there will be a much smaller body of material to be examined for possible discard.

Standard material which circulates is more likely to have a record with an 050 LCC class number. Classifiers could become familiar with the classification before having to assign so many class numbers originally.

You might want to do down-the-shelf reclassification of the reference collection, and of the reserve collection during the holiday before school reopens. But for the bulk of the collection, I suggest delaying down the shelf reclassification for from two to five years. Undertaking that at the outset can bog you down with esoteric little used material.

If a branch of any system uses an alternate classification, e.g., Moys law classification, the collection should use the same classification for law. The Moys' "K" intershelves with LCC, replacing LCC's K. The difference between LCC's K for law and Moys' K for law, is that LCC's arranges law by jurisdiction, and Moys' arranges common law jurisdictions together by topic.

In Canada there is an adaptation of LCC's KF (U.S. law in LCC) which also arranges all common law jurisdictions together by topic. This means that in libraries using that adaptation, no use is made of LCC's KD British law and KE Canadian law, If you see such a KF number in 055, it should *not* be used unless the library uses that adaptation.

If a university has a medical school, it might want to consider NLM (National Library of Medicine) classification. It uses "W" for medicine, replacing LCC's R, and like Moys, intershelving with LCC. As with Moys, if the branch library uses NLM, medical books in the main collection should also be in NLM.

This would effect the reclassification of DDC 340 and/or 610.

SLC assigns class numbers for book jobbers on the basis of FTP files, and could do the same for any library reclassing to LCC.