File Name: link_USapp_forpri_CNpub_forpri

Observations: 749,636

Description: This file determines links between file USapp_for_priority and file CNpub_for_priority. That is, we take the foreign priority claims in the US applications, which list a claim date, a claim country, and a patent application number, and we take the foreign priority claims in the Chinese published patents, which also list a date, country, and an application number.

We first attempt to match on (1) priority date, (2) country (3) application number (after we do some cleaning of the text field for application number for both countries). In cases where we did not get a match, we also look at the title of the patent and the list of inventors. Specifically, we also included cases where there is a match on (1) priority date, (2) country, (3) title (first 40 characters match except for minor discrepancies, and (4) name of the first inventor.

Note a given Chinese patent might match to multiple to US applications, if the Chinese patent and multiple US applications cite the same foreign priority claim (or overlapping foreign priority claims). Analogously, a given US application might link to multiple Chinese patents.

The table at the bottom of this file shows that for Chinese patents claiming foreign priority (outside the US) in publication years 2005 and after, we obtain a match to a patent application in the U.S. file, with the same foreign priority claim, in 80 percent of cases. In the paper we focus only on Chinese patents published 2005 and after. Not every patent filed in China claiming foreign priority outside the U.S. will be filed in the US as well. So we expect the match rate to be less than 100 percent, even apart from measurement error where we miss true matches.

Note the match rates in the early 2000s are low, beginning with 10 percent in 2000. One issue is that the USPTO only began publishing patents in 2000, and in the early years, not every patent application was published.

Variables

Variable	Type	Len	Columns in Ascii File	Description
app_numfix	Char	12	1-12	link variable to Chinese patent (unique index of CNpub_basedat)
Country2	Char	2	13-14	Country code of foreign priority claim
for_pri_rec_trun	Char	40	15-54	truncated record of foreign priority claim in Chinese patent data used for matcing
for_pri_index_CN	Num	8	55-62	Corresponds to for_pri_index in file CNpub_for_priority
app_publication_num	Char	20	63-82	link to US application (along with app_publication_kind). app_publication_num*application_kind is unique index of USapp_basedate
app_publication_kind	Char	3	83-85	see above
priority_app_num	Char	30	86-115	priority application number as listed in the US file
priority_index	Num	8	116-123	priority_index variable in USapp_for_priority
for_priority_date	Char	10	124-133	date of foreign priority claim

Table Showing Distribution of Matches by Year of Chinese Patent Publication

We start with the 1,080,629 foreign priority claims in CNpub_for_priority and select out 757,902 cases where the foreign priority claim is not from the US. We do this because we expect that matches to the US application file for patents claiming US for priority will be found in file link_USapp_appnum_CNpub_forpri. (i.e. will go to the application number of the US application, rather than the foreign priority file). We next select the 608,180 unique values of app_numfix. For each app_numfix, we ask if the given app_numfix has at least one match in USapp_forpri_CNpub_forpri) and table below reports the results.

	Counts		Percent
	Not Matched	Matched	Not Matched	Matched
All	221,198	386,982	36.37	63.63
pub_year	88,671	3,084	96.64	3.36
1999 and earlier
2000	14,985	1,743	89.58	10.42
2001	15,483	5,797	72.76	27.24
2002	10,501	13,116	44.46	55.54
2003	7,695	23,625	24.57	75.43
2004	8,285	30,254	21.50	78.50
2005	11,389	49,287	18.77	81.23
2006	11,815	51,140	18.77	81.23
2007	13,157	56,385	18.92	81.08
2008	12,887	50,876	20.21	79.79
2009	14,073	54,740	20.45	79.55
2010	12,257	46,935	20.71	79.29