DO PATENT POOLS ENCOURAGE INNOVATION? EVIDENCE ...
DO PATENT POOLS ENCOURAGE INNOVATION? EVIDENCE ...
DO PATENT POOLS ENCOURAGE INNOVATION? EVIDENCE ...
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A related test explores whether the decline in patenting was more<br />
pronounced for subclasses that included more than one pool patent. In subclasses<br />
with one pool patent, the technology was already owned by a single firm so that<br />
the creation of a pool may not have had any direct effect on invention. In<br />
subclasses with two or more pool patents, however, the creation of a pool may<br />
have combined two patents that were owned by competing firms before the<br />
creation of the pool.<br />
Patent data confirm that the decline in patenting after the creation of the<br />
pool was significantly stronger for subclasses that included two or more pool<br />
patents. Pool subclasses with one pool patent generated an average of 2.47<br />
patents per year in the first ten years after pool creation compared to 2.60 patents<br />
per year prior to pool creation; pool subclasses with 3 or more pool patents<br />
generated 3.27 patents per year compared to 5.14 patents per year prior to pool<br />
creation (Table 3). OLS estimates indicate that subclasses with 1 pool patent<br />
produced -0.36 fewer patents after the creation of a pool, while subclasses with 2<br />
pool patents generated 0.27 fewer patents and subclasses with 3 or more pool<br />
patents generated 2.02 fewer patents (significant at 5 percent, Table 5, column 2).<br />
G. Robustness checks<br />
The first robustness check restricts the sample to pool subclasses and<br />
cross-reference subclasses, effectively using cross-reference subclasses as the<br />
control for pool subclasses. Pool subclasses and cross-reference subclasses<br />
generated similar numbers of patents per year; in the ten years before the<br />
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