DO PATENT POOLS ENCOURAGE INNOVATION? EVIDENCE ...

90
Pool Start Year
10
9
Pool Start Year
2.5
80
9
8
70
8
7
2
Industry Patents
60
50
40
7
6
5
4
Pool Patents
Industry Patents
6
5
4
1.5
1
Pool Patents
30
3
3
20
2
2
0.5
10
1
1
0
1921 1923 1925 1927 1929 1931 1933 1935 1937 1939 1941 1943 1945 1947
0
0
1921 1923 1925 1927 1929 1931 1933 1935 1937 1939 1941 1943 1945 1947
0
40
Industry Patents Pool Patents
Industry Patents Pool Patents
Wrinkle Paint Finishes (1937-55) Fuse Cutouts (1938-48)
Pool Start Year
4.5
9
Pool Start Year
1.2
35
4
8
1
30
3.5
7
Industry Patents
25
20
3
2.5
2
Pool Patents
Industry Patents
6
5
4
0.8
0.6
Pool Patents
15
1.5
3
0.4
10
1
2
5
0.5
1
0.2
0
0
0
0
1921 1923 1925 1927 1929 1931 1933 1935 1937 1939 1941 1943 1945 1947
1921 1923 1925 1927 1929 1931 1933 1935 1937 1939 1941 1943 1945 1947
Industry Patents
Pool Patents
Industry Patents
Pool Patents
Ophthalmic Frames (1938-48) Furniture Slip Covers (1938-49)
Notes: Pool subclasses are listed as the primary (original) subclass by at least one pool patent before the
formation of a pool. Industry patents (unbroken black line) includes all patents issued in those pool
subclasses. Pool patents (broken black line) includes patents issued to the pool in those pool subclasses.
The timing of invention is measured by the year of the patent application.
6