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Mercy Mhuru
Last seen: 05/01/2020 - 15:23
Joined: 05/01/2020 - 15:08
Explanation of citations categories

I am a new user of patents data and wanted to ask if there is a data dictionary explaining the data. For example, when using the US citations data there is a variable called category, which shows whether a patent was cited by examiner, by applicant, by other or null. What does it mean when a patent has null as category of citations? Or when it is cited by other? If I'm using citations data as a proxy for knowledge/technology flows is it prudent to use patent citations with a null or other category? If I drop the "null" and "cited by other" citations, I lose about 43% of the citations, which may bias my results. Here is a snapshot of the citations per category:

category    Freq.     Percent    Cum.
                
    NULL    21,863,085    20.44    20.44
    cited by applicant    36,981,491    34.58    55.02
    cited by examiner    22,668,307    21.19    76.21
    cited by other    25,441,798    23.79    100.00
    cited by third party    2,845    0.00    100.00
imported from    a related application    718    0.00    100.00
                
    Total    106,958,244    100.00
 

Sun, 05/03/2020 - 09:31
Russ
Last seen: 12/06/2024 - 09:12
Joined: 11/14/2017 - 22:15
data dictionary

Hi Mercy,

   I don't think pvteam is around to answer for the api team. There is a link to a data dictionary on the left hand side of the downloads page or directly at https://www.patentsview.org/data/Patents_DB_dictionary_bulk_downloads.xlsx.  It says that the category field is only available for patents issued in 2002 and up which is why you see so many nulls.  The patentsview database is built from the granted patent xml files the uspto made available for patents issued in 1976 onward.  So patents issued since 1976 have patent citiations in uspatentcitation.tsv but they'd only have a non null category if the citing patent was issued in 2002 or later.

I found a page on the uspto site that mentions the different verisons of dtds the xml files used over time.  It's at https://www.uspto.gov/learning-and-resources/xml-resources. I was surprised the dtds didn't mention the possible categories used or what they mean.

I hope this helps,
Russ