Are All Patent Examiners Equal?: The Impact of Examiner
Characteristics on Patent Statistics & Litigation Outcomes
Iain Cockburn, Boston University & NBER
Sam Kortum, U Minnesota & NBER
Scott Stern, Northwestern, Brookings & NBER
Why look at examiners?
PTO examination process is fundamental to the IP system, but its relationship to policy proposals and economic assessment are poorly understood
Research on the “PTO production function” can help to– Evaluate policy initiatives aimed at PTO operations– Inform academic research on economic impact of IP
Differences among examiners may be an important driver of patent quality and breadth
Rules versus Discretion
The patent examination process is highly structured, but some discretion is necessary
Despite careful monitoring and detailed rules (MPEP) examiners use prior knowledge and individual judgment to search prior art, determine scope of allowed claims, etc.
– Exercise of discretion may have consequences for the scope of intellectual property rights
Impact of discretion may depend on examiners’ experience, specialization, and training
Methodology
Build qualitative understanding of examination process
Identify examiners responsible for patents whose validity is reviewed by CAFC (1997-2000)
Evaluate relationship between CAFC-tested patent statistics and examiner characteristics
Test whether examiner characteristics are associated with CAFC validity findings
Key Qualitative Findings
“There are as many patent offices as there are patent examiners” Extensive “apprenticeship” system w/ mentoring of junior examiners Prior art search technology and method varies across…
– art areas – time
Examiner job design varies in the degree of…– technological specialization– collaborative interaction
“All applications are created equal”
… potential for idiosyncratic exercise of discretion
Examiner heterogeneity: Qualitative Insights
May result in persistent variation in– breadth of claims allowed (“generosity”)– approval times– degree of “self-citation”
But…link to patent statistics or litigation outcomes claimed to be “noisy”
– “Finding a needle in a haystack”
Data
182 patents where validity tested by CAFC (1997-2000)– 50% found invalid, more likely for
computer/communication, less likely for drugs/medical
196 examiners on these patents, responsible for ~290,000 patents 1976-2000
Distribution of Examiner Experience
Distribution of Technological Specialization
Distribution of Examiner Cites / Patent
ANOVA tests
Examiner “id” accounts for 8-10% of variation in
– Approval times– Citations Made– Citations Received
Strongly statistically significant even after controlling for technology class and application year
Do Observable Examiner Characteristics Impact Patent Statistics?
Citations on CAFC-tested patents are strongly associated with Examiner Cites per Patent
Even after inclusion of detailed technology and cohort fixed effects
Approval time on CAFC-tested patents uncorrelated with examiner characteristics
Nuanced relationship with generality and originality of “forward” citation
Do Examiner CharacteristicsImpact Litigation Outcomes?
How do CAFC Validity Patents Compare to “Average” Patents?
CAFC SAMPLE
TYPICAL PATENT
Claims 20.5 9-14
Citations Received
14.0 6-8
Citations Made
16.7 6-8
Approval Time 2.21 1.76-2.05
CAFC Patents have more claims, cite more prior art,are more highly cited, and are associated with slightly longer approval times.
Do Examiner Characteristics Impact CAFC Validity Decisions?
Probability of patent being found invalid
– NOT related to examiner’s experience, recent workload, propensity to self-cite, approval time
– Significantly higher when examiner has higher “lifetime” average level of citations received per patent
(controlling for technology class and application year)
Do Examiner Characteristics Impact CAFC Validity Decisions?
INVALID VALID
EXAMINER
CITES / PAT 6.89 5.72
Are CAFC rulings sensitive to “over-generous” examiners?
YES!– Econometric procedure links probability of invalidity to that part of
“forward” citations received which is attributable to the examiner’s propensity to allow patents which attract many cites
So, if….– citations received is an indicator of breadth of the patent AND– exercise of discretion by examiners results in variation in the
average # of citations that “their” patents receive
One increase in Examiner Cites / Patent associated with a 25% decrease in the probability of validity
Origins of “Generosity”
Differences in information (access to prior art) The Apprenticeship system Consistency across patents of a given examiner, not
necessarily consistency across examiners– Level of review not dependent on social or economic value of
invention
Effort: easiest thing to do is “allow” patents Incentives
Consequences of “Generosity”
Process by which application are allocated to examiners is particularly important
Specialization induces variation in the “size” of the rights awarded
– particularly of concern for immature technologies
Potential burdens on – the judicial system – private intellectual property contracting
Implications
Training, mentoring and monitoring are at the core of preserving “not too much, not too little”
Should level of review depend on the potential economic and social value of application?
CAFC rulings are responsive to exercise of examiner discretion
Conclusions
Examiners are heterogenous
Preliminary evidence does not support naïve hypotheses about negative impact of inexperience
Courts tend to invalidate patents associated with “generous” examiners
– Important role for judicial review in “trimming” discretion