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Last seen: 12/14/2017 - 13:42
Joined: 11/14/2017 - 11:22
patent associations with null entries

I noticed patent associations, cited_patents for example, have "empty" array entries in the middle of the array.


Here'e what I'm seeing with this specific patent for citations{"patent_number":"4893934"}&f=["patent_number","cited_patent_category","cited_patent_date","cited_patent_kind","cited_patent_number","cited_patent_sequence","cited_patent_title"]

This returns 15 citations with indexes 3,4,5,6,7 having null values, except for sequence

Why are there entries with all null values except for sequence?

Also, when i leave out "cited_patent_sequence" ({%22patent_number%22:%224893934%22}&f=[%22patent_number%22,%22cited_patent_category%22,%22cited_patent_date%22,%22cited_patent_kind%22,%22cited_patent_number%22,%22cited_patent_title%22]) the results are slightly different in that there's only one "null" entry




Last seen: 08/14/2018 - 19:54
Joined: 11/14/2017 - 19:15

Hi Mike,

I noticed the same thing.  I think it depends on the issue year of the referenced patent.  The uspto (and hence patentsview) has full data for patents issued in 1976 and above.  Only a handful of fields are available for pre 1976 patents at (issue date, uspcs, cpcs and obviously patent number).  If you look at the references in the patent in your example you'll see that the nulls correspond to pre 1976 patents.  See

In your second url all the pre 1976 patents seem to get rolled up into a single entry perhaps because there is nothing to distinguish them from each other (lacking the sequence number).  Possibly because of a join in the database to wildly speculate.

For the pre-1976 references it would be nice if the patent number and referenced issue date were returned along with the sequence number.  It makes sense to me that the other fields would be null since that data isn't available.  


Role: moderator
Last seen: 08/14/2018 - 06:53
Joined: 10/17/2017 - 07:47


Russ is correct that the reason for the null entries is that those cited patents were issued before 1976 and so we do not have as much information about them. It would be good to return the patent number and issue date for those patents (which we do have), and we will add that to our list of potential improvements!




Last seen: 08/14/2018 - 19:54
Joined: 11/14/2017 - 19:15
Partial fix

It looks like there has been a partial fix for this. The cited_patent_number is coming back now on the pre-1976 referenced patents!  The cited_patent_date, however, is not being returned.  I suspect this is due to the underlying data.  The references usually just contain the month and year, not the full date.  The uspto's patft does have issue dates for all patents but I don't know if the data is available in bulk or if it could be incorporated into the data being returned.