Introduction
The new implemenation of ClarivateTM’s Derwent World Patents Index® (DWPI) on STNext provides an integrated solution for the traditional Derwent content and the Derwent Patents Citation Index®, which is seamlessly merged into the framework of the classic DWPI. The new synergies make it much easier to combine a standard DWPI patent search with a citation search, e.g. a DWPI prior art search can easily be extended with prior art from citation data. Also, ranking of DWPI patent search results according to citation counts is now more straightforward.
A citation search directly performed in DWPI can answer questions like:
- What has been cited by whom, who is citing a particular invention?
- Who is working in a similar technology area?
- Who are my closest competitors?
- Which are the most relevant patents of a patent portfolio?
- Which additional prior art could be derived from a citation search?
The Derwent Patents Citation Index is a unique collection of patent and literature citations from 32 patent authorities with superior data quality. Backward and forward patent citations are being enriched with Derwent value-added content, like Derwent patent assignee codes, which is extremely useful for comprehensive citation analysis. An elaborated set of citation counts supports users to identify inventions of high technological relevance. Powerful display options ensure the most efficient analysis of citation search results. Citation information is made available on two different levels of detail: each Derwent family record is associated with a de-duplicated set of citations, while individual publications are linked to the full citation information.
The most prominent features of the Derwent Patents Citation Index include:
- Cited and citing patent references enriched with Derwent value-added data
- Derwent assignee and inventor names plus patent assignee codes (PACO)
- Cited NPL references including
- representative set of NPL citations for the Derwent family
- access to standardized XP document numbers and DOI links
- Citation counters calculated for the Derwent family records
- Counters for backward, forward and literature citations
- patent number/patent authority/Derwent family counts
- total reference count for cited patent and NPL references
Derwent family based display options:
- full citation details for individual publications
- de-duplicated set of cited/citing patent references plus NPL references
- HIT display feature
Sophisticated search options
- high precision searches with the (P)-proximity operator
Additional citation information with relevant information of the search report
- origin of citation (applicant, examiner, opposition, third party observation)
- examiner citations with citation categories
- examiner citations with links to relevant claims and passages of the patent full-text
- examiner’s field of search for four different patent classifications (IPC, CPC, Japanese FI terms, US classification)
Citation Coverage
The Derwent Patents Citation Index is a unique collection of patent and literature citations from 32 patent authorities which has been compiled on the basis of the Derwent family. Citation coverage is based on EPO’s citation data (REFI) plus national office data feeds to enhance timeliness and completeness.
Citation references originate from examiner search reports, applicant citations, opposition procedures (EP) and third party observations (EP, US, WO).
Patent Citation Index – Patent Country Coverage
| Country Coverage | Period | Country Coverage | Period | Country Coverage | Period |
| AM | 2007 – to date | EP | 1978 – to date | NL | 1974 – to date |
| AT | 1993 – to date | ES | 1993 – to date | NO | 2010 – to date |
| AU | 1993 – to date | FR | 1973 – to date | NZ | 1994 – 1996 |
| BE | 1988 – to date | GB | 1979 – to date | PH | 2010 – to date* |
| BY | 2002 – to date | GC | 2004 – to date | RU | 2009 – to date* |
| CA | 1994 – 1996 | JP | 1994 – to date* | SE | 1994 – 1996 |
| CH | 1985 – to date | KG | 2004 – to date | SG | 2000 – to date |
| CN | 2010 – to date | KR | 2006 – to date* | TW | 2000 – to date* |
| CZ | 2000 – to date | KZ | 2007 – to date | US | 1974 – to date |
| DE | 1974 – to date | LU | 1999 – to date | WO | 1978 – to date |
| DK | 2000 – to date* | MD | 2016 – to date | ZA | 1994 – 1996 |
| EA | 2002 – to date | MY | 2006 – to date* | DD, FI, IE, IT, TJ | Limited coverage |
Search and Display Options
Citation searching in the DWPI is fully supported by various search fields providing access to cited patent numbers, cited inventor and assignee names, cited Derwent accession numbers, etc. High precision searching is possible with the (P)-proximity operator which links all data elements of an individual citation, like cited patent number with cited patent assignee, cited inventor and citation category.
The entry point of a citation search could be a technology or patent assignee search in DWPI. In a first step, this search result can be limited to those records with citation information applying the field availability field (/FA). FA indicates the presence of cited patents (CDP/FA), citing patents (CGP/FA) or cited non-patent literature (CDL/FA).
As citation displays can be very lengthy, the HIT display option is extremely useful to focus on the citations relevant for the search.
Patent Literature Citations (Cited and Citing)
Searching cited and citing patent publications is inline with the corresponding master patent fields of the Derwent patent family. While cited patent search fields have a .D attached, citing patent search fields use the suffix .G. PAX.D and PAX.G are select fields only (see HELP 3EFIELDS).
| Field Description | Master | Cited | Citing | Display |
| Derwent Accession Number | AN | AN.D | AN.G | CDP (cited) CGP (citing) |
| Inventor Name | IN | IN.D | IN.G | |
| Patent Assignee Name | PA | PA.D | PA.G |
| Patent Assignee Code | PACO | PACO.D | PACO.G | CDP (cited) CGP (citing) |
| Paten Country | PC | PC.D | PC.G | |
| Patent Kind Code | PK | PK.D | PK.G | |
| Patent Publication Date | PD | PD.D | PD.G | |
| Patent Publication Number | PN | PN.D | PN.G | |
| Patent Number/Kind Code | PNK | PNK.D | PNK.G | |
| Patent Publication Year | PY | PY.D | PY.G |
Non-Patent Literature Citations
Non-patent literature citations are available for 24 patent authorities, including XP document numbers, links to Internet resources and digital object identifiers. Single terms can be searched with the field /CDL, left truncation and simultaneous left and right truncation (SLART) is available. Standardized XP document numbers and digital object identifiers have their own search fields.
| Field Description | Search | Display |
| Cited non-patent literature | CDL | CDL, CDLA |
| XP document number | XP | XP, CDL, CDLA |
| Digital object identifier | DOI | DOI, CDL, CDLA |
Example Use Case:
Search for inventions which cite NPL references of Prof. Matthias Beller:
Examiner Citation Categories
Citations from patent search reports have citation categories assigned which indicate their relevance to the examined patent application. These categories are useful to refine a citation search to the most relevant citations.
| Citation Category | Description |
| X | relevant if taken alone |
| I | relevant to the inventive step |
| Y | relevant if combined with another document |
| A | technological background |
| O | non-written disclosure |
| P | intermediate document |
| T | theory of principle |
| E | earlier document published on or after the filing date |
| D | document cited in application |
| L | document cited for other reasons |
| R | used in CN A publications to reference dual filings |
Patent examiners assign one or more citation categories to individual citations. Accordingly, search capabilities allow to search with one or more categories, e.g. I/CAT, AI/CAT, (A(P)I)/CAT. The (P)- proximity operator can be used to refine citation searches with category information.
| Field Description | Search | Display |
| Citation Category | CAT | CDP (cited) CGP (citing) CDL (literature) |
| Citation Category, cited | CAT.D | |
| Citation Category, citing | CAT.G |
Example Use Case:
Search for inventions which cite BASF patent publications as X or I documents:
Origin of Citations
Citation references originate mainly from examiner search reports and applicant citations. Documents cited in opposition procedures are only available for oppositions filed at the European Patent Office. Citations of third party observations are available for EP, US and PCT publications.
The origin of the citation is searchable with a single letter code (A, E, O, T, U) or the descriptive text (APPLICANT, EXAMINER, OPPOSITION, THIRDPARTY, UNKNOWN) in the field /ORC. A particular citation can have multiple origins assigned when deduplicated on the invention level, e.g. AE/ORC.
| Field Description | Search | Display |
| Origin of Citation | ORC | CDP (cited) CGP (citing) CDL (literature) |
Example Use Case:
Search for which publications of Siemens AG (PACO = SIEI-C) have been cited in EP opposition procedures:
Citation Counts
Citation counts are widely used as indicators to assess the value of a particular patent or patent portfolio. Especially a high number of forward citations is seen as indicator for a high patent value.
Derwent Patents Citation Index offers meaningful citation counts for patent and literature citations based on Derwent family records. The DWPI accession number counts are invention-based citation counts which are independent of the size of the patent family.
| Field Description | Search | Display |
| Cited DWPI Accession Number Count | ANC.D | CITC |
| Citing DWPI Accession Number Count | ANC.G | |
| Cited Patent Counts | PNC.D | |
| Citing Patent Counts | PNC.G | |
| Cited Patents Country Count | PCC.D | |
| Citing Patents Country Count | PCC.G | |
| Cited Literature Reference Count | CRC | |
| Citing Reference Count (total) | REC |
Examiner's Field of Search
The Derwent Patents Citation Index includes the patent classifications searched by the patent examiner for a particular invention, mentioned in the search report: search criteria for IPC, CPC and national office patent classifications (FI-terms, US classification) are made available. This information can be used to perform a similar search to the one the examiner performed.
The patent classification codes of the examiner’s field of search have been standardized according to the STNext standard as far as possible. IPC-, CPC- and FI-terms are searchable at subclass, main group and subgroup level, e.g. A61K0035-16/EXF.IPC, A61K0035/EXF.IPC, A61K/EXF.IPC.
| Field Description | Search | Display |
| Examiner’s field of search, IPC | EXF.IPC | CDP (cited) CGP (citing) CDL (literature) |
| Examiner’s field of search, CPC | EXF.CPC |
| Examiner’s field of search, JPC | EXF.JPC | CDP (cited) CGP (citing) CDL (literature) |
| Examiner’s field of search, USPC | EXF.USPC |
Example display of the Examiner Field of Search:
Derwent Family Members with Citation References
Derwent family members with citation references, either being cited or citing references, are searchable with the respective .F-fields: PN.F, PK.F and PC.F.
These citation family members have a (P)-proximity link to the corresponding citations. This can be useful to analyze the citation behavior of a patent office. Also a very useful application is to identify additional Chinese dual filings which are currently not part of the Derwent family (see example below).
| Field Description | Search | Display |
| Patent country of family member | PC.F | CDP (cited) CGP (citing) CDL (literature) |
| Patent kind code of family member | PK.F | |
| Patent number of family member | PN.F |
Example Use Case:
Identify CN A publications which cite Chinese utility models as R document (dual filing):
Display Options - Overview
Users have two principal options to display citation data (except for citation counts):
- Full citation details are provided with individual publications and retain the link between cited/citing publication.
- Abbreviated display formats provide de-duplicated citation information on Derwent family level
As citation displays could be very lengthy, users could choose the HIT display option to focus on the citations relevant for the search.
| Detailed | Abbreviated | D/A | |
| Citation Counts | CITC | CITC | CITN CITNA |
| Examiner’s Field of Search | EXF | EXFA | |
| Cited Patents | CDP | CDPA | |
| Literature Citations | CDL | CDLA | |
| Citing Patents | CGP | CGPA |
Monitoring Options
Citation information is updated when any new cited or citing patent information is received. This update process generates the update date UPD, when new or updated cited patent or non-patent literature references enter the DWPI (e.g. from equivalents). When citing patent information is updated, the update date UPG is generated. Both dates, UPD and UPG, can be used for citation alerts.
Citation monitoring can be done manually using saved queries or scripts. For setting up automatic alerts the CREATE AN ALERT feature of CAS STNext can be used. Alternatively, you can use the SDI command to set up a citation alert (see HELP SDI).
| Field Description | Search/Display |
| Update date, cited | UPD |
| Update date, citing | UPG |
Example Use Case 1:
Manual Alert: Search for new inventions which cite patents of Evonik (PACO = EVON)
Example Use Case 2:
Automatic Alert on CAS STNext: Create an alert for new inventions citing you own key patents
Additional General Use Cases Leveraging Citations
The following use cases demonstrate queries you can construct for specific valuable use cases.
Example Use Case 1: Identify key patents of a patents of a patent portfolio or technology, e.g., key patents of Biontech’s patent portfolio
Example Use Case 2: Who are the key competitors of BASF SE in the area of exhaust gas treatment technologies?
Example Use Case 3: Which companies cite biocatalysis patents of Evonik Degussa Gmbh most often?
a. Strategy with Evonik as cited patent assignee, self citations removed:
=> S (EVON OR DEGS)/PACO.D AND (C12N/IPC,CPC,FCL OR D05/MC)
=> S L1 NOT (EVON OR DEGS)/PACO
=> ANA L2 PACO => D 1-
b. Strategy with Evonik as patent assignee and analysis of citing assignees
=> S (EVON OR DEGS)/PACO AND (C12N/IPC,CPC,FCL OR D05/MC)
=> ANA L1 PACO.G => D 1-