The Most Difficult Patent Examiners at the USPTO, Ranked by Allowance Rate

Every patent prosecutor has drawn one: the examiner who rejects on the first action, rejects again on the final, and treats a strong argument as a formality to get past. You can feel the prosecution getting longer before you have written a word of response.

The most difficult patent examiners at the USPTO are not a matter of reputation. They show up in the data, in one number above all others: allowance rate, the share of disposed applications an examiner allows rather than abandons. It is the single best early read on how hard a prosecution will run, and it lets you set client expectations and shape a strategy against the record instead of against a hunch.

Key findings

• The most difficult USPTO examiners are identified by allowance rate: the share of disposed applications they allow rather than abandon.
• Across USPTO applications disposed 2020 to 2024, the ten examiners with the lowest allowance rates each allowed fewer than 9 percent of the applications they disposed.
• The single most difficult examiner allowed one application out of 145, an allowance rate of 0.7 percent.
• Even measured against their own art units, every examiner on the list is a dramatic outlier. In the strictest art unit on the list, which allows 35 percent of applications, the listed examiners still allow fewer than 9 percent, roughly a quarter of their own unit's rate.
• Of the 7,862 examiners with 100 or more dispositions, 105 allowed fewer than a quarter of their applications and 653 allowed fewer than half, against a USPTO-wide allowance rate of 82 percent for the window.
• Interviews raise allowance rates by up to 9 percentage points on average across the USPTO, but the lift is uneven, and for the hardest examiners it can disappear.

Who are the most difficult examiners at the USPTO?

The most difficult examiners at the USPTO are those with the lowest allowance rates: the share of disposed applications they allow rather than abandon. This is a ranking by that one number, not a judgment of an examiner's skill or temperament. Allowance rate measures the docket as much as the person: the hardest examiners cluster in the technology areas where rejections are hardest to clear, so a low rate partly reflects the subject matter an examiner is handed. To account for that, the table below shows each examiner against the allowance rate of their own art unit, not just the office-wide average.

It is worth saying before the list what the list can and cannot do. A low allowance rate is a warning, not a plan. It tells you the odds you are walking into. It does not tell you how to change them, and the rest of this piece is about that difference.

“A low allowance rate is a warning. It is not a plan.”

Measured across utility and plant applications disposed 2020 to 2024, excluding Supervisory Patent Examiners and counting only examiners with 100 or more dispositions, the ten lowest allowance rates, each shown beside their own art unit's rate, belong to the examiners below.

Ranking by allowance rate. Utility and plant applications disposed January 2020 to December 2024. Art unit allowance rate covers the same window. Source: Juristat analysis of USPTO data, pulled September 11, 2026.

Even against their own art units, these examiners are outliers. The strictest unit on the list, art unit 3629, allows 35 percent of its applications, yet the two examiners drawn from it allow under 9 percent, about a quarter of that. Across the whole USPTO, the allowance rate for this window was about 82 percent.

"8.9 percent is the highest allowance rate among the ten most difficult examiners."

How is examiner difficulty measured?

Examiner difficulty is measured by allowance rate over a fixed window of disposed applications. We analyzed utility and plant applications disposed between January 2020 and December 2024, excluded design patents, reissues, reexaminations, and provisional applications, excluded Supervisory Patent Examiners, and counted only examiners with 100 or more dispositions so a handful of hard cases could not distort a rate. That left 7,862 examiners. All figures come from public USPTO data, frozen as of September 2026.

What do the most difficult examiners have in common?

The hardest examiners cluster in predictable places. As the table shows, that clustering is real but it does not explain them away: even against their own units these examiners sit far below the line.

Five of the ten work in Technology Center 3600, which covers electronic commerce and business methods, the area where Section 101 subject-matter eligibility rejections are most common and hardest to clear. Three more sit in Technology Center 3700, mechanical engineering and manufacturing, and the remaining two in Technology Center 1600, biotechnology and organic chemistry. Difficulty is not spread evenly across the office; it pools where the law of eligibility is most contested and the prior art is deepest.

The scale is worth holding in mind. Of the 7,862 examiners who met the 100-disposition threshold, 105 had an allowance rate below 25 percent and 653 below 50 percent. Against a USPTO-wide rate of 82 percent for the window, the examiners on this list are outliers even among the strict.

Check your examiner before you respond

Pull a free examiner report to see the allowance rate, office action history, and prosecution record for the examiner on your matter.

What should you do when you draw a difficult examiner?

The ranking sets the odds. Changing them is a separate question, and it runs on the rest of the record: whether interviews help, which response types overcome the examiner's rejections, and how the art unit has treated arguments like yours.

Do examiner interviews improve allowance rates?

Often, yes. Across the USPTO, interviews with examiners can raise allowance rates by as much as 9 percentage points. That is the average, and the average can be exactly wrong for the examiner in front of you.

Consider an examiner near the top of this list. In the art unit around them, interviews lift allowance rates sharply. For this examiner, the record shows almost no applications allowed at all, whether or not an interview or an RCE was filed, because the barrier is not the kind of thing a single conversation moves. The general rule, that interviews help, is true on average and close to meaningless here. Only the examiner's own record, read for this kind of rejection in this art unit, tells you which case you are in, and it is worth reading before you spend a client's money finding out.

Which response types work against a tough examiner?

It depends on the examiner, which is the point. The pattern worth finding is specific: for this examiner, on this kind of rejection, in this art unit, what has actually worked. That is prosecution context, not an examiner statistic, and it is the difference between knowing the odds and changing them.

“Up to 9 percentage points is the allowance-rate lift interviews can add across the USPTO. For the hardest examiners, that lift can vanish.”

The number is where the work starts

Knowing the odds is easy. Changing them is the work, and the work runs on the full prosecution record behind the number, not the number alone.

See the record behind the number

Allowance rate is where the analysis starts, not where it ends. Pull a free examiner report to see the full prosecution record: interview and RCE win rates, outcomes by response type, and art unit trends for the examiner on your matter.

Better data in, better decisions out. Smart In. Smart Out.

Frequently asked questions about difficult patent examiners

How are the most difficult patent examiners determined?

By allowance rate over a fixed window of disposed applications, limited to utility and plant applications and to examiners with 100 or more dispositions. The examiners with the lowest allowance rates are the most difficult.

What is a typical patent examiner allowance rate?

The USPTO-wide allowance rate was about 82 percent for applications disposed 2020 to 2024. The most difficult examiners sit far below that, each allowing fewer than 9 percent of their applications, and far below their own art units as well.

Do examiner interviews increase allowance rates?

Across the USPTO, interviews can raise allowance rates by as much as 9 percentage points, but the effect varies sharply by examiner and can disappear for the hardest ones. The examiner-specific record tells you whether an interview is worth it in a given case.

Can you change the outcome with a difficult examiner?

Yes. Allowance rate sets the odds, but response-type selection, interview strategy, and art unit context change them. The full prosecution record for the examiner is what informs that strategy.

Where can I find a patent examiner's allowance rate?

Basic examiner statistics are widely available. A free Juristat examiner report shows the allowance rate plus the full prosecution record behind it, including win rates by response type.