File Name: CNpub_IPC-class

Observations: 7,415,286 IPC classifications

Unique Index: app_numfix*ipc_index

Description: The file lists all IPC classification for each patent, with a separate record for each IPC class of each patent.

Variables

Variable	Type	Len	Columns in Ascii File	Description
publication_num	Char	20	1-20	Publication number of patent
publication_date	Num	8	21-28	Publication date of patent (month, day, year in ascii file)
app_numfix	Char	12	29-40	Application number in consistent 12-character format
ipc_num	Num	8	41-48	Total number of IPC classifications listed on the patent
ipc_class	Char	20	49-68	IPC classification
ipc_index	Num	8	69-76	Order that given IPC class is listed on the patent.