Geography Reference
In-Depth Information
Table 16
.
1
US inventors' patenting activity at EPO, 1978-2002 (selected IPC classes)
1978-1985
1986-1995
1996-2002
1978-2002
Patents
Pharmaceuticals (1)
1784
8739
9360
19883
Organic chemistry (2)
6152
13433
9845
29430
Biotechnologies (3)
1525
7013
8498
17036
Total
9461
29185
27703
66349
Inventors
Pharmaceuticals (1)
2409
11897
14494
24762°
Organic chemistry (2)
5679
15289
15640
29799°
Biotechnologies (3)
2145
10549
12787
22066°
Total
9430*
32215*
36661*
63188*°
Notes:
(1)
IPC: A61K = preparations for medical/dental/toilet purposes
(2)
IPC: C07, excl.C07B
(3)
IPC: C12M-S = biochemistry; microbiology; enzymology; genetic engineering
*
Total no. of inventors < sum of tech. classes, as one inventor may patent across classes.
°
Total no. of inventors < sum of time intervals, as one inventor may patent at dif erent times.
others (Breschi et al., 2003). Here we emphasize that many inventors active in one i eld
also sign patents in one or both of the other i elds. This explains why the total number of
inventors in our sample (last line of Table 16.1) is smaller than the sum of all inventors
in each technological class, whatever time period we observe. In particular, in between
1978 and 2002, 13439 inventors (21 per cent of the total sample) have patented in more
than one of the three i elds.
The selected inventors represent the universe of all US inventors listed on EPO docu-
ments in the selected i elds and years. The resulting ai liation network of patents, appli-
cants and inventors, is therefore comprehensive of all social ties established through
joint inventive activity, as it is the one-mode projection of the same network onto just
inventors. From this network we have derived measures of social distance between all
patents in the sample.
A major problem with measuring the geographic dispersion of patents and patent cita-
tions relates to the way patents are assigned to locations. Patent documents report the
postal address of each inventor, from which we derive the MSA (metropolitan statistical
area) and state location of each inventor in each year of activity.
However, patents can have multiple inventors, each one with a dif erent address.
Therefore, the location of patents in geographic space cannot be resolved in an unequiv-
ocal way. In case of multiple inventors, JTH assigned each patent to the country/state
in which pluralities of inventors resided, with ties assigned arbitrarily. Here, we take a
slightly dif erent approach and argue that two patents match geographically to the extent
that they share
at least
one inventor's location.
Descriptive statistics
The vast majority (73 per cent) of all inventors in organic chemistry, pharmaceuticals,
and biotechnology are found to sign patents for only one company throughout their
