Do Patent Examiners’ Political Beliefs Affect Green Innovation?

Patent systems rely on objective legal and technical standards to evaluate new technologies. In practice, however, patent examiners have substantial discretion in interpreting patentability criteria and determining whether an invention meets those standards. Because these bureaucratic decision-makers hold different political beliefs, their ideological preferences may influence how they assess applications, particularly when reviewing politically salient technologies.

Green innovation provides a setting in which such ideological effects may arise. Environmental technologies, especially those addressing climate change, have become highly politicized in the United States. If examiner ideology influences patent evaluation, the patent system may significantly shape the incentives for developing socially valuable technologies. Our study investigates whether patent examiners’ political ideology influences the approval of green patent applications and, in turn, subsequent green innovation by inventors and firms. 

Measuring Politics in Patent Examination

The study analyzes more than 5 million non-provisional utility patent applications filed with the USPTO between 2001 and 2023. We combine patent examination records from the USPTO’s Patent Examination Research Dataset (PatEx) with examiner information from the U.S. Office of Personnel Management and voter registration data from L2 to identify the political affiliation of individual examiners.

The empirical strategy exploits the quasi-random assignment of patent applications to examiners within specialized technological units at the USPTO. Because applications are assigned largely independently of their underlying quality, this setting allows to examine whether rejection decisions vary systematically with examiners’ political ideology while accounting for other factors that may affect patent approval outcomes.

Ideology and Green Patent Rejections

The results reveal a clear ideological divide in the evaluation of green innovation. Republican examiners are about 2 percentage points more likely to reject green patent applications than independent examiners, representing a 7.7% increase relative to the average rejection rate. This disparity is stronger for technologies directly related to climate change than for other environmental technologies, such as pollution control, and becomes more pronounced during Republican presidential administrations and periods of heightened political polarization over climate change.

The study then examines whether the higher rejection rate among Republican examiners reflects stricter evaluation standards. If so, the green patents they approve should be of higher quality. However, the results do not support this explanation: green patents approved by Republican examiners do not receive more citations or generate higher economic value than those approved by other examiners.

We further find no significant differences between Republican and other examiners in first-action allowances, whereas applicants are less likely to amend and resubmit after rejections by Republican examiners. One possible explanation is that Republican examiners more often invoke Section 101 of U.S. patent law (subject-matter eligibility) when rejecting green patents. Section 101 determinations involve considerable discretion and are more difficult for applicants to address through amendments or appeals, making these rejections harder to overcome.

These examination outcomes also have broader consequences for subsequent innovation. Inventors and firms that receive a rejection from a Republican examiner are less likely to continue pursuing green innovation: over the following three years, affected inventors filed about 14% fewer green patent applications, while public firms reduced green patent filings by around 7.7 percent. 

Innovation Depends on Institutional Neutrality

The study shows examiners’ political ideology affects the evaluation of green patent applications. Republican examiners are more likely to reject green patents without approving higher-quality ones. These differences arise in part from the use of more discretionary grounds for rejection that are harder for applicants to address, reducing the likelihood of amendment and subsequent green patent applications by inventors and firms. Economically, the study estimates that ideological distortions in the patent review process have resulted in roughly 10,000 additional rejected green patent applications and at least $20 billion in lost economic value for public firms. The analysis also finds economically meaningful declines in subsequent innovation, with green patenting decreasing by about 14.1% for affected inventors and about 7.7% for public firms.

More broadly, the findings highlight the role of institutional gatekeepers in shaping the evolution of innovation ecosystems. When outcomes in the patent review process become less predictable or more difficult to address, inventors and firms may be less willing to pursue new innovations, particularly in politically salient fields such as climate innovation. Such responses can slow technological progress in economically and socially important areas.

These findings provide new insights into the importance of maintaining political neutrality in technocratic decision-making. Greater transparency and clearer guidance in applying discretionary legal grounds, particularly Section 101, may help ensure technologies in politically or ideologically sensitive areas are assessed consistently and based on their scientific and technological merits.

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Tao Shu is the Vice President and Presidential Chair Professor at The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen).

Fei Xie is Chaplin Tyler Professor of Finance and Iannaccone Faculty Fellow at the University of Delaware, and an ECGI Research Member.

Song Zhang is Assistant Professor of Finance at the Alfred Lerner College of Business and Economics, University of Delaware.

Wenrui Zhang is an Associate Professor of Finance at the Department of Finance and Real Estate of Colorado State University (CSU).

This blog is based on a paper presented at the 4th HKU Summer Finance Conference. Visit the event page to explore more conference-related blogs.

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