Certificate of Correction

According to PTO figures, the Office has issued around 25,000 certificates of correction on issued patents each year since 2001. On a per patent basis, about 15% of issued patents are associated with a certificate of correction.*

Generally, a certificate of correction can be used to correct a minor mistake such as a “clerical or typographical” error or other minor error. In Superior Fireplace, the court held that a certificate of correction that broadens the claim is only permissible when it is clear from the specification and prosecution history how to correct the error. Similarly, in Central Admixture Pharmacy the CAFC found that the correction from osmolarity to osmolality was void because the error “was not clearly evident to one of skill in the art and the result was to broaden the claims.” The relief for an improper certificate of correction is simply to cancel the certificate. 

Over the past several years, a number of automated and out-sourcing services have emerged to check against PTO printing errors and other typographical errors. What are the best services and best practices regarding corrections?


  • * To account for the time delay in obtaining corrections, I looked at only patents numbered 6,000,000 – 7,000,000 for the per patent estimate.

14 thoughts on “Certificate of Correction

  1. 14

    Hi I am a freelance Patent and Published Application proofreader, I have around five years of experience in this field. I am doing proofreading at a nominal fees:

    1. Face Page and Claims Only – 20 USD
    2. Whole Patent upto 20 pages – 25 USD
    3. Whole Patent between 20 and 50 pages – 30 USD
    4. Whole Patent more than 50 pages – 50 USD
    5. Published Application – 25 USD

    mail me at nafisha83@gmail.com

  2. 12

    Patinti (www.patinti.com) now delivers quality patent translations for information purposes from Japanese into English for 7 USD per 100 English words. Please ask for other language pairs.

  3. 11

    We have had excellent service in proof reading from Intellevate, a division of CPA. They do it from India and use the PTO website to get all the information and provide a color coded correction on the printed patent that identifies both PTO errors and your own errors and they also provide a completed Certificate of Correction if you like–all for a modest fixed fee.

  4. 10

    A yet another option would be that a clean copy of the specs-to-be-granted be provided to the patent office – wonder how many out there would be takers for this additional procedural step?

  5. 9

    I did a utility application for a college student many years ago. He patented his improved derailleur invention which was his senior engineering project. He wanted a patent for his resume.

    When the PTO issued the patent, the wrong drawings were included and the correct drawings were omitted. When I asked for the patent to be regranted with the correct drawings, I was told the only remedy was a certificate of correction which the PTO graciously offered to do for no charge.

    Surprisingly, the client was a mensch (sp?) and just chalked it up to an early lesson of dealing with the government.

  6. 8

    Until recently I proofread Japanese patent translations here in Japan. The expectations about what is required vary massively amongst patent firms here – it’s utterly dependent on who heads the translation section. Some firms don’t consider any sort of proofreading process by a native English specialist (or equivalent) to be necessary, or even desirable. Others think it’s desirable, but are unwilling to pay for the service. I once had somebody seriously offer me 2 yen a word to do some work on the side for them – they claimed it was twice what they were paying some sucker in Britain… Well, you get what you pay for. It shouldn’t come as a surprise that such outfits need to request lots of correction certificates – but my hunch is that not as many as required, since once the patent issues they still don’t pick up on the mistakes…

    Cheers, Luke

  7. 7

    We’re not talking about perfect grammatical English. If the examiners used that standard, nearly every application I have ever examined would fail. No, foreign applications are a special breed of incomprehensible garbage that rise far above the level of minor spelling or grammatical errors. I’ve had cases with 5+ pages of 112 1st and 2nd rejections because both the disclosure and claims were worthless. How good do you think the prior art is going to be in cases like that? That is, of course, even assuming I have any time left for searching after wading neck-deep through the written equivalent of raw sewage.

    There’s also the fact that foreign applications tend to have short specifications that disclose pretty much nothing that isn’t already stated in the claims – sometimes word-for-word. Must be quite an invention you have there, when the claims end up having to satisfy enablement without a spec.

  8. 6

    Random Examiner – the specification need not be written in perfect, grammatical English, contrary to an Examiner’s assertion to the contrary. The Examiner’s job is to find applicable references, and to disregard minor typographical and grammatical errors. If the specification is understandable, not only does the Examiner not do the applicant a service by pointing out every error, the applicant need not even correct those errors.

  9. 5

    randon.examiner — why don’t you and/or some of your other examiner colleagues write an article and have it translated and published in a Japanese patent journal explaining to Japanese clients how important it is to file U.S. applications that are very readable

  10. 4

    “It’s too important.”

    Obviously, Patent_Medicine is not Japanese. That would be an interesting statistic for you Dennis – see how many of those certificates of correction are to japanese inventors/assignees. I’d put the number in the 70-80% range. Most certificates of correction that I see clean up craptacular translations.

    Kind of puzzling when you think of it: with all this squabble about pendency and quality, you’d think practitioners would want to file cases with correct spelling & grammar. If you wanted an examiner to spend time doing something, do you want him/her correcting your japenglish or finding good art that will lead to a valid patent? I know your clients dont want to pay for it, but doing it removes one more layer of rework everyone has to deal with.

  11. 3

    >When clients do not want to pay for proofreading
    >the entire patent, we suggest that they at least
    >pay for proofreading the claims or proofread the
    >claims themselves.

    What MP said. When I was out-house, I made it part of my “file closeout” procedure, along with checking the PTA. I felt so strongly about it I would do it anyway even if the client didn’t want to pay for it. Now that I’m in-house, I do it myself. It’s too important.

  12. 1

    We have seen a number of examples, unfortunately, where the Patent Office printed the patent with an incorrect set of claims from the application (e.g., the original claims, or a first set of amended claims, rather than the last set of amended claims), as well as where the Patent Office printed the patent with a set of claims from some other, unrelated, random application.

    When clients do not want to pay for proofreading the entire patent, we suggest that they at least pay for proofreading the claims or proofread the claims themselves.

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