Report:Derwent World Patents Index/Special Indexing/Derwent Manual Codes
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Derwent Manual Codes
Derwent Manual Codes are a proprietary method of classifying patent documents used by the Thomson Derwent indexing staff. The coding system is similar to the IPC classification system: it is hierarchal in structure and comparable in its "level of specificity" to the subject areas.
Searching the Manual Codes applied to chemical documents in Derwent sections A-M (in the CPI, Chemical Patents Index) is a separate subscription option. However, manual codes applied to electrical (sections S-X) and mechanical documents (Section Q, transportation only) are open access and do not require a special subscription.
Manual Codes are structured similarly to IPC codes, with a section letter (A), subsection number (ANN), group letter (ANN-A), subgroup number (ANN-ANN), division letter (ANN-ANNA), subdivision number (ANN-ANNAN), and, for some electrical codes, a final 9th character, a letter, beginning with codes used in 1996 (ANN-ANNANA). Like IPC codes, more than one Manual Code may be applied to a record.
The major differences between the Derwent Manual and IPC classification systems are:
- The Manual Codes do not currently cover as wide a range of subject matter as the IPC codes.
- Manual Codes are assigned by a small, highly trained pool of Thomson employees, whereas IPC codes are assigned by staff with variable levels of expertise and training in patent offices around the world.
- Manual Codes are only assigned once, to a patent family "basic" member, whereas IPC codes are assigned individually to publications by the various national patent offices.
- Manual Codes are assigned only to the inventive features described by the "basic" document. In contrast, the IPC system allows examiners to classify non-inventive content.
Derwent Manual Codes are suited to broad subject searching, and because they are hierarchal in structure, the codes can be truncated at a higher level to include all sub-categories in a search. Note that because the codes are relatively broad, truncating the Manual Code term at a high level may often give a hit count too large to review without further limitations. However, the terms are considered very useful when combined with other parameters, for example, they can be used to exclude false hits from unwanted subject areas during a keyword search.
The Manual Codes have been applied back to the earliest records in the DWPI file, with the exception of Section Q transportation codes, which have only been in use since 2006, and catalyst codes, which have been in use since 1977.
According to subject expert Stephen Adams, there were about 7,500 chemical indexing terms and 9,500 electrical indexing terms in the Manual Code as of 2006. The mechanical indexing effort currently only extends to transportation documents in section Q. A regular schedule for revising the codes has not always been in place, but it seems that going forward an annual revision effort will be made to keep the codes current as technology evolves.[1]
A Manual Code thesaurus is included with the Derwent file, and may be accessed to learn more about code definitions. (Access to the thesaurus may not be available on all search platforms.)
Manual Code revisions have taken place each year since 2005 "to accommodate changes in technology, provide finer subject matter breakdown and thus improve information retrieval."[2]
Sources
- ↑ Adams, Stephen R. Information Sources in Patents (2nd edition). K.G. Saur, Munich. 2006.
- ↑ Manual Coding System Revision. Thomson Reuters website, http://science.thomsonreuters.com/support/patents/dwpiref/reftools/classification/code-revision/. Accessed on August 13, 2010.
