Certificates of Correction

by Dennis Crouch

A substantial percentage of patents continue to pass through the post-issuance correction process that leads to a Certificate of Correction.


The chart above shows the number of certificates of correction issued by the USPTO each year with a forecast through the end of 2016.* After a patent issues, a patentee can petition for a correction of “clerical or typographical nature, or of minor character” or clear mistake by the USPTO. There is no fee if the error is a USPTO mistake and currently a $100 fee for correcting applicant-mistakes (no small/micro entity fee reduction).

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.  In Cubist Pharma v. Hospira (Fed. Cir. 2015), however, the court held that a structural diagram could be re-drawn in its sterioisomer form to correct a misunderstanding of the chemistry at the time of filing. I wrote on Patently-O that this decision highlights “that the ‘error’ being corrected need not be simply a typo.”

The number of corrections has remained relatively steady over the past 15 years. Since the number of issued patents issued has risen so dramatically during that time, this steady-state of correction filings means that the average number of corrections per recently issued patent has continued dropped steadily for the past decade with the odd exception of patents issued in 2009.   About 14% of patents issued 1990 to 2005 went through the correction process. That percentage is now down under 10%.

Timing: Based upon a small sample (750 corrected patents issued 2010-2014).  The median correction time is 49 days (from the PTO receipt of the request for correction until issuance of the certificate).  90% were complete within 6-months. 95% within 1-year.

* The chart includes utility patents as well as reissue, design, and plant patents.


6 thoughts on “Certificates of Correction

  1. 4

    Without going back into the files, my sense is that about half of the Certificates of Correction we receive result from reconsideration of patent term extension. Most of the rest result from the USPTO transforming the marked up copies of the claims to a clean form. Spaces and punctuation get inserted or deleted, language that has been stricken in the last amendment is found in the published claim, and in some cases the last amendment is not reflected in the published claims.

    Although we proofread the claims carefully for typographical errors, more and more of our clients prefer that we not spend the time and money proofreading the specification. This may contribute to the reduction in the number of corrections per issued patent.

  2. 3

    A couple of questions:-

    Any idea what proportion of the certificates correct errors in the original disclosure as compared with printer/USPTO errors?

    (Puts head above parapet expecting to be shot at – I’m only asking a question). Does anyone wonder why patents are published (with possibility of printer/USPTO error) when the whole file is available for inspection?

  3. 2

    Back around 1990, a client’s patent was issued with the wrong drawings — PTO error, hardly minor. I was advised by the PTO that the only remedy was a Certificate of Correction. While the client was understanding, I was particularly disappointed that the PTO treated such an egregious error so cavalierly.

  4. 1

    Hmm… wonder if the declining rate of CoC requests might reflect a partial changeover from “old school” patent work (2 paralegals went over every issued patent with a fine toothed comb and CoC requested for even minor typos) to a newer school that is more tolerant of (what are thought to be) non-material typos?

    Also, Dennis, note this sentence really needs a closer like “was acceptable” or the like.

    “In Cubist Pharma v. Hospira (Fed. Cir. 2015), however, the court held that a correction to a structural diagram that had misidentified a sterioisomer of the claimed daptomycin compound. “

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