Who Decides Your Reexam: The 110+ USPTO Examiners You Should Know

The 598 utility-patent ex parte reexamination filings projected for 2025 will land across a population of roughly 110 active reexam examiners at the USPTO. The procedure looks uniform on the page, same statute, same procedural sequence, same outcomes vocabulary, but the experience of running a reexam in front of one examiner versus another can be materially different. This is a profile of the population, why examiner identity matters, and what the data shows about the variance.

A small, specialized pool

Active reexam examiners at the USPTO are a comparatively small group. Most have prior experience as primary examiners in the relevant technology, and many have specialized in reexamination practice for years. The pool turns over slowly. New examiners join occasionally, but the core caseload concentrates on the most experienced reviewers.

The top five examiners by volume handle 70+ reexams each. The most active, Peter C. English, has handled 114 reexams since 2012. The next tier (approximately ten examiners) each handle 30-70 reexams. The remainder distribute across the population, with many examiners handling fewer than 20 cases.

What the data shows about variance

Three operational metrics vary materially across the 110+ active examiners.

Pendency. The average is 17.4 months from filing to final disposition. Individual examiner averages range from approximately 12 months on the fast end to over 24 months on the slow end. A reexam filed in front of a 22-month examiner takes roughly 50% longer than one filed in front of a 14-month examiner. That difference compounds when a PTAB appeal is added.

Rejection basis preference. Of all rejections, 72% are 103 (obviousness), 15% are 102 (anticipation), approximately 5% are 112 (written description, enablement, indefiniteness), and 8% fall under other grounds (double-patenting, mixed bases, 305-scope). Individual examiners run dramatically different mixes. Some are above 90% 103. Others reach 102 and 112 in nearly equal share. A request that depends on a 112 vulnerability has different odds in front of different examiners.

Appeal rate. Across closed reexams, the average PTAB appeal rate is 24%. About a quarter of cases reach the PTAB. Individual examiners produce widely different appeal rates. Some sit near 10%, others approach 50%. The high-end appeal rate means the realistic cost projection on those cases must include a probable PTAB proceeding.

Why examiner assignment is mostly invisible to practitioners

Most ex parte reexams are assigned to an examiner after the request is filed and before the SNQ determination is issued. The assignment is administrative and not publicly previewed. Practitioners typically learn the assigned examiner from the SNQ determination paperwork.

This means examiner-driven variance hits the case after the request strategy is locked in. The practical implication: requests should be drafted with awareness of the examiner pool's variance, not optimized for a single assumed examiner. A request that lands on the wrong examiner cannot be re-drafted; only the response strategy can adapt.

Two examples

Peter C. English. 114 reexams handled. Pendency averages 22.3 months (5 months longer than the average). Office actions per reexam average 2.2 (against the 1.5 average). Appeal rate runs 49%. Rejection mix runs 12/79/8/1 across 102/103/112/Other (against the 15/72/5/8 average). For a patent owner with a case in front of English, the realistic timeline runs closer to two years before disposition, with a coin-flip probability of a PTAB appeal.

William Doerrler. 113 reexams handled. Pendency averages near 13 months, among the fastest. Cert rate at 90% of closed cases. Practitioners running a case in front of Doerrler should plan for a more compressed timeline and a higher probability of certificate without a prolonged office action sequence.

Both examiners are senior and experienced, and both produce reliable, defensible outcomes. They are simply different reviewers, and the data shows it.

What this means for practitioners

Three operating implications:

1. Identify the examiner early. Once SNQ is granted, the examiner is named. The case strategy should adapt to known patterns before the patent owner statement is filed or, on the challenger side, before any reply is needed.

2. Adjust the cost projection. Pendency and appeal rate variance both move the realistic cost forecast for the case. Two patents with similar prior art profiles can have different cost trajectories depending on examiner assignment.

3. Pre-position the response. Examiners with higher 112 rates respond differently to specification-based arguments than examiners who almost never reach 112. Patent owner statements should anticipate which grounds the examiner is most likely to develop.

The procedure is one thing. The examiner running it is another. Knowing the difference is most of the strategic advantage available in ex parte reexam. (How much one examiner can move the case: a Peter C. English case study.)