Embedded Files
The file pdp76_06 has been revised as of August 2010. The following are important changes:
The variable allcites is NOT corrected for citation truncation (in the previous version it was) but the correction factor hjtwt is included to allow the user to correct.
The variable allnscites has been removed, as it is only really useful if you have a specific dataset of US companies, and was inaccurate otherwise.
New variables have been added:
nclaims - number of claims in the patent (from the website, probably not corrected for any re-exams or disclaimers)
status - whether the patent is missing (M) or withdrawn (W). There are very few of these; they often will not have any other data on the file.
term_extension - the number of days that the patent term has been extended due to USPTO delays.
The cat, subcat, nclass, and subclass variables now pertain to the current classification (CCL), not the original classification (OCL). The variables corresponding to the original classification are labelled cat_ocl, etc. This change was made because the CCL is more complete and probably more accurate about the current state of the system.
Finally, this file includes multiple records for patents with multiple assignees. There are 63,266 such patents, with up to 13 assignees. This is about 2 per cent of the total number, and increases the number of observations in the file from 3,210,361 to 3,279,509. For patent analysis, you will wish to remove the duplicate observations, but to count patents held by an entity, you may wish to keep all the entries. Other than assgnum (which is an older and inaccurate sequence number), pdpass, state, and country, all data for a given patent number are identical.
Patent classification:
The USPTO changes its classification system from time to time to accommodate the growth in new technologies, adding classes, and occasionally deleting old classes if they become too full (creating a whole new set of classes to replace them).
The variables designated "OCL" are based on the original classification at the time the patent was examined and issued (the field of search shown on the USPTO website). Therefore the classificaiton system used will vary across the patents in the file according to their vintage.
The variables designated "CCL" are based on the USPTO classification system as of 2008. This means that all the patents on this file will have a consistent classification applied if you use the ccl variables. The category and subcategory assignments are listed in this spreadsheet. Note that the categories do not fully correspond to early technology classes (such as 2006 or nclass) because, of course, the USPTO continually revises the technology classes.
IPC codes are assigned via a concordance from the USPTO codes. The USPC to IPC Concordance is based on the International Patent Classification Eighth Edition (please see note at the bottom of this page ).
Correcting for citation truncation:
HJT refers to Hall, Bronwyn, Adam Jaffe and Manuel Trajtenberg, "The NBER Patent Citation Data File: Lessons, Insights and Methodological Tools," NBER Working Paper 8498. This paper describes the citation variables, their computation and weights. The variable hjtwt is a multipler that can be applied to the number of citations from US patents through 2006 received by the patent (allcites), in order to correct for the truncation of post-2006 cites using the methodology described in the HJT data description. HJT estimated a 6 field specific obsolescence-diffusion model with year and lag dummies and used the estimated model to predict a grossing up factor for the cites based on the patent's grant year and technology category. As discussed in the HJT paper, this variable is not very accurate for the last three years of the sample (2004-20066), as three years is too short a time to get a good measure of actual cites.
The formats of the new utility patent data files are:
1. pat76_06_assg.dta (and ASCII equivalent)
This file has one record for each assignment of each utility patent. Patents that are assigned to more than one party have multiple records. This file lists only the first technology class.
The data description of this file is:
obs: 3,279,509 Patents granted through 2006
vars: 32 4 Aug 2010 14:25 size: 377,143,535 (28.1% of memory free)------------------------------------------------------------------------------- storage display valuevariable name type format label variable label-------------------------------------------------------------------------------allcites int %9.0g Cites 1976-2006 (not adj for truncation)appyear int %8.0g Year patent applied forasscode byte %8.0g Original assignee code (1-7)assgnum byte %8.0g assg/assignee seq. number (imc)cat byte %8.0g HJT tech category (1-6) for CCLcat_ocl byte %8.0g HJT tech category (1-6) for OCLcclass str11 %11s Primary current US class/subclass (Alpha)country str2 %9s assg/countryddate float %d patn/disclaimer dategday byte %8.0g Day patent grantedgmonth byte %8.0g Month patent grantedgyear int %8.0g Year patent grantedhjtwt float %9.0g Citation truncation weight as of 2006icl str18 %18s clas/international classificationicl_class str4 %9s Main 4-char IPCicl_maingroup float %9.0g Main group within 4char IPCiclnum byte %8.0g clas/icl seq. number (imc)nclaims int %9.0g patn/number of claimsnclass int %9.0g US 3-digit current classification (CCL)nclass_ocl int %9.0g US 3-digit original classification (OCL)patent long %12.0g Patent number (7-digit)pdpass long %12.0g Unique assignee numberstate str2 %2s assg/statestatus str1 %1s auth/status: m missing, w withdrawnsubcat byte %8.0g HJT tech subcategory (11-69) for CCLsubcat_ocl byte %8.0g HJT tech subcategory (11-69) for OCLsubclass float %9.0g Subclass for US current class (CCL)subclass1 str9 %9s Subclass for US current class (CCL) - Alphasubclass1_ocl str9 %9s Subclass for US original class (OCL) - Alphasubclass_ocl float %9.0g Subclass for US original class (OCL)term_extension int %9.0g patn/extension of patent term in days under 35 usc 154(b)uspto_assignee long %12.0g Original assignee number
-------------------------------------------------------------------------------Sorted by: patent2. pat76_06_ipc.dta
This file has one record for each IPC class for each patent. The data description is:
obs: 4,857,833 Patents granted through 2006,
including IPCs vars: 14 4 Aug 2010 14:27 size: 272,038,648 (48.1% of memory free)------------------------------------------------------------------------------- storage display valuevariable name type format label variable label-------------------------------------------------------------------------------appyear int %8.0g Year patent applied forcat byte %8.0g HJT tech category (1-6) for CCLgyear int %8.0g Year patent grantedicl str18 %18s clas/international classificationicl_class str4 %9s Main 4-char IPCicl_maingroup float %9.0g Main group within 4char IPCiclnum byte %8.0g clas/icl seq. number (imc)nclass int %9.0g US 3-digit current classification (CCL)numipc byte %9.0g Number of international patent classespatent long %12.0g Patent number (7-digit)pdpass long %12.0g Unique assignee numbersubcat byte %8.0g HJT tech subcategory (11-69) for CCLsubclass float %9.0g Subclass for US current class (CCL)uspto_assignee long %12.0g Original assignee number-------------------------------------------------------------------------------Sorted by: patent pdpass iclnumPage updated
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