This document explains research analyzing the impact of prior art disclosure by applicants on patent examination and patent stability using Japan Patent Office's prior art disclosure system implemented in September 2002 as a natural experiment.
Identifying prior art in patent examination is essential for evaluating novelty and inventive step of inventions. Policies differ significantly across countries: the US has comprehensive disclosure obligations with penalties for insufficient disclosure, Europe has no disclosure obligations, and Japan has mandatory disclosure since the 2002 system reform but operates as an incentive-dependent system without substantial penalties.
The research uses instrumental variable methods to empirically demonstrate that applicant disclosure behavior varies according to invention value. For high-value inventions, active literature disclosure occurs for early right establishment and stability enhancement, while low-value inventions may have incentives to "slip through" examination. Literature disclosed by applicants was categorized, and the "disclosure quality" was defined as the proportion where applicant-disclosed literature matches examiner-utilized literature for analysis.
Analysis results show that system reform increased disclosure quality overall, with particularly significant effects for high-value inventions. High-quality disclosure shortened examination periods by approximately 26 days on average, reduced claim scope and examiner amendments, significantly contributing to examination efficiency. Furthermore, it decreased invalidation trial request rates by 0.036 percentage points and appeal trial request rates by 1.617 percentage points, contributing to patent stability.
Conversely, increased disclosure of literature not utilized in examination extended examination periods by approximately 4 days on average and increased claim scope expansion and examiner amendments, causing inefficiency. However, positive effects from high-quality disclosure outweighed negative effects, with system reform providing overall positive impact on patent examination and patent stability. Additionally, applicant-disclosed literature was utilized in future examinations beyond the relevant patent, with an average of 1.4 future citations per literature confirmed.
The article is evaluated as demonstrating that even formal disclosure obligations without penalties can promote appropriate prior art disclosure through systematic clarification, contributing to examination efficiency and patent stability, while indicating the need for system design that suppresses large-volume disclosure of irrelevant literature and promotes high-quality disclosure.