Guest Post: To File a CON? Empirical Popularity and Prosecution Outcomes

Guest Post by Kate S. Gaudry, Ph.D and Thomas D. Franklin, Kilpatrick Townsend & Stockton LLP.  The opinions expressed in this article are those of the authors and do not necessarily reflect the views of Kilpatrick Townsend & Stockton LLP or its clients. This article is not intended to be and should not be viewed as legal advice.

An increasing number of statistics are available on trends in patent application filings and prosecution outcomes. However, it is uncommon to see the data segregated based on type of application. Specifically, how frequently are continuation applications filed? And does previous prosecution experience with a parent application result in favorable prosecution outcomes?

Answers to these questions may be pertinent when developing strategies as to whether to file a continuation application. Frequent continuation filings may indicate that competitors consider it important to have the claiming flexibility of keeping a family alive or a trend toward filing omnibus applications (disclosing multiple ideas or idea aspects per specification). Meanwhile, any advantage of a continuation must be considered in view of its cost, which depend in part on prosecution expectations.

Accordingly, we requested data from the USPTO that identified, for each fiscal year and technology center (TC), the number of new applications filed (excluding RCEs) that were: (1) a continuation application; (2) a divisional application; (3) a continuation-in-part application; or (4) none of the above. Further, we requested, for each of these application types: (1) the number of patents issued and number of abandonments between July 1, 2014 and July 8, 2015 (to generate a final-disposal allowance rate for this time period); and (2) the average number of office actions issued for each application that received a notice of allowance during this time.

Continuation Applications: Increasingly Common

Overall, in fiscal year 2015, 20% of the filed applications were continuation applications. Divisionals comprised 6% of the data set, and continuation-in-part applications accounted for 3% of the applications. The remaining 72% lacked a priority claim to another non-provisional U.S. application. (FIG. 1)

FIG. 1

FIG. 1

FIGs. 2A and 2B respectively show the unnormalized and normalized distributions of filing types per fiscal year. The percentage of applications that were continuations doubled from 9% in 2005 to 18% in 2015.

Patently-O App-Type FIG 2

FIG. 2

The increased popularity of continuation applications is observed across all TCs. (FIG. 3.) The most substantial increases is observed in TCs 2100 (Computer Architecture, Software, and Information Security) and 2600 (Communications), where the contribution of continuation applications to total filings increased by 142% and 132%, respectively, between 2005 and 2015.

Patently-O App-Type FIG 3

FIG. 3

Continuation applications were most common in TCs 1600 (Biotechnology and Organic Chemistry), 2100 (Computer Architecture, Software, and Information Security) and 2400 (Computer Networks, Multiplex Communication, Video Distribution and Security), where continuation applications accounted for 29%, 28% and 30% of the applications, respectively. Continuation applications were least common in TC 3600 (Transportation, Construction, Electronic Commerce, Agriculture, National Security and License & Review), accounting for only 14% of the applications. The infrequency of TC 3600 continuation applications may be due, in part, to the rarity of allowances in the business-method art units.[1]

Continuation and Original Applications have Similar Prosecution Statistics

Potentially, experience with a parent application (and, typically, a same examiner) may guide claiming strategy for a continuation. Thus, perhaps, continuations represent a two-fold cost-savings opportunity: a savings in drafting and in prosecution costs. Assessing the latter potential savings requires evaluating allowance rates and office-action counts of continuation applications. Accordingly, we evaluated prosecution statistics from a recent time period (July 2014-July 2015) for each of the application types.

Overall, the final-disposal allowance rate for continuations is slightly higher than that for original applications (80% versus 74%). (FIG. 4A.) The average office-action count per patent is slightly lower for continuation applications (1.85 versus 1.96). (FIG. 4B.)

FIG. 44

FIG. 4

Discussion: Why and How to File Continuations

Continuation applications provide a variety of advantages, including an opportunity to seek a new scope of protection in view of business priorities and to strategically draft claims in view of ongoing or threatened challenges to a patent. This latter upside is becoming increasingly significant as the number of post-grant challenges continues to grow.

Should an applicant decide that the advantages of keeping a family alive are sufficiently important, claiming strategy for the child application must then be identified. Slightly tweaking an allowed claim may result in minimal prosecution costs. However, a fast allowance will lead to an overall cost of the family exploding (assuming repeated continuation filings). Seeking substantially broader protection, meanwhile, may lead to extended and frustrating prosecution. Our data showing that continuation and original applications have similar prosecution statistics suggest that applicants are not consistently choosing an easy or hard continuation-claiming path, though it may be explained by split uses of these types of claim-drafting techniques.

Another approach to continuations is to seek protection of a completely different idea in the specification. This could allow a resulting patent family to provide diverse protections towards different elements of an applicant’s technology. However, a new focus requires that the new idea be supported and enabled by the original specification. In an era where flat fees and legal bidding wars are common, it is our hypothesis that few applicants are willing to pay the higher drafting fees for preparation of such enhanced applications. However, we believe that this is a strategic approach and should be more frequently used.

Consider a case where an applicant is seeking patent protection of two ideas. A traditional approach is that separate patent applications be drafted for each idea. Another approach is to draft a single “omnibus” patent application that describes both ideas. One idea can be the focus of an original filing, and another the focus of a continuation filing. Then, by investing in keeping a single family alive (via the original and continuation filings and/or additional continuation applications), claiming flexibility for each idea is preserved. Further, if ideas within an omnibus application are related, drafting fees may be less than preparing two independent applications. The application may also illuminate synergies and interactions between the ideas, which may further expand claiming possibilities.

Concluding Thoughts

Our data shows that continuation-application filings are becoming increasingly common. Filing continuation applications offers many advantages, particularly now that patents are frequently challenged. However, blindly filing continuation applications will lead to an explosion in costs. Strategic filing of omnibus continuation applications, however, will offer long-term cost savings and prosecution advantages. Therefore, applicants should consider intelligently identifying and organizing sets of ideas into omnibus applications.

[1] Gaudry KS. 2015. Post-Alice, Allowances are a Rare Sighting in Business-Method Art Units. IPWatchDog. <>

17 thoughts on “Guest Post: To File a CON? Empirical Popularity and Prosecution Outcomes

  1. 8

    There can be serious pitfalls with filing omnibus/kitchen-sink applications, in that anything you don’t claim can fall into the public domain.

    A good article describing the benefits and pitfalls of such applications can be found here: link to

  2. 7

    I’d be interested in knowing how the continuation rate varies based on the date of the original application. With the increase in patent applications, I wonder if the continuation rate is actually growing faster than what the graphs show. If newer patents are getting more continuations, then we might be on the front end of a flood.
    Jim – an inventor, not a lawyer

  3. 6

    One factor to consider is that I continue to see A LOT of examiners essentially rubber-stamping continuations, regardless of what the claims say. Their mindset seems to be “Oh I remember this case. I allowed the parent so I’m sure these claims are patentable as well.” In some instances a string of 4-5+ continuations are granted without any real substantive examination after the parent (unless you count double patenting rejections). And the applicants obviously know this is how the game is too often played. If a new examiner pushes back and dares to actually examine the claims properly, the application is abandoned (and often that is end of the string of continuations).

  4. 5

    This current % and increase in continuation applications is particularly surprising in view of the availability of requests for continued examination (RCE). RCEs were supposed to reduce the number of continuations, saving paperwork and other expenses for both the applicants and the PTO. In both cases only the claims may be validly substantively changed, not the specification. The main difference is that traditional continuations can substantially increase the PTO delay in prosecution and keep the case pending much longer. Especially since the U.S. PTO does not adequately enforce examining applications in their true, original filing date, order, and has on various occasions misrepresented continuations as “new” applications. Lemelson and Hyatt applications being prime examples. Furthermore, is not filing a separate later application for previously unclaimed subject matter in the original specification usually more appropriate for a divisional, rather than a continuation, and less likely trigger double patenting rejections by so doing?
    Does this not suggest that a main motivation for filing continuations is for delay of issuance, so as to be able to later on add or amend claims to cover later commercial products of others [“from the catbird seat” as it has been put] and/or to introduce and overcome later found prior art, including art asserted in a patent suit on a related patent, completely ex parte? As Hal Wegner has noted, this ability to add or amend surprising new claims in kept-pending sequential continuations and/or divisionals for up to 20 years after the original filing date and application publication is more or less unique to U.S. practice. It is unrestricted since the “Late Claiming Doctrine” was disposed of by the Fed. Cir. years ago.
    If the PTO would treat continuations as continuations, that is, in their originally claimed filing date, this could be easily corrected and continuations would undoubtedly decrease.

    1. 5.1

      Your distance from prosecution is showing.

      A continuation application is a separate application from its parent (and always has been).

      There is NO “delay of issuance” for that parent.

      Further, continuations ARE treated as of their parents filing date.

      Please stop attempting to kick up dust so unnecessarily.

      1. 5.1.1

        I did not even suggest that continuations are not a “separate” application [in the technical sense that the PTO gives it new serial number], in fact I specifically noted that the PTO has even treated them as “new” applications. That, of course, is conveniently overlooking the fact that a continuation must have the same specification invention disclosure and is thus is really the “same case” [as I put it]. Furthermore a continuation’s parent application is often abandoned after a continuation is filed, which indisputably does delay issuance of any patent on the disclosed invention. Asserting that “continuations are treated as of their parent filing dates” in PTO prosecution is refuted simply by comparing average continuation original [parent] filing dates with continuation issue dates, not even to mention the many Lemelson and Hyatt examples I noted. If there were any truth in that assertion, continuations, especially sequential serial continuations, that are filed four or more years after their original parent application was filed would regularly be picked up first by examiners and receive first office actions shortly after the continuation was filed.


          You did suggest so in your “same case” and “delay of issuance” position which has NO reasonable application here.

          But you keep digging and trying to support your position, only showing your gap of working knowledge even more so.

          It turns out that perhaps it is a good thing that you no longer represent yourself as a patent attorney.

          (whether or not a parent is abandoned is immaterial to the point here – you really do need to grasp the separateness factor).

          As to any sense of “submarines” in the Lemelson sense, you should be aware that the law was changed some time ago for that.

          As it is, your post merely reflects your continuing animus against patents and patentees. Are you even aware of the bias you present?


          Furthermore a continuation’s parent application is often abandoned after a continuation is filed, which indisputably does delay issuance of any patent on the disclosed invention.

          I don’t understand why this would be done “often,” these days. Are you sure this is a frequent occurrence?


            Dan, that is just my perception, but a statistical survey might prove me wrong. If one can get all the claims one wants in the continuation, and not need to issue the parent application, one can avoid any maintenance fees for the parent, and avoid any double patenting issues and any possible enforceable term loss from a terminal disclaimer. That may be more important to some clients than others. But of course there are other times and other clients that might want to issue a parent application fast with narrower claims, perhaps even by paying for the new accelerated examination, and to keep a continuation pending for tougher prosecution of broader claims and perhaps an appeal.


              You cannot get “all the claims one wants” – no new matter and for your continuation, you are limited with what you filed (as far back as the time benefit you are hooking into)

              Terminal disclaimer loss is what it is. Your child continuation still “ticks” from the parent, even if you abandon that parent. Any small difference (e.g. that might arise from PTA) is NEGLIGIBLE for our discussion.

              ANY TIME fast narrower claims are desired, that option is available – and is a non sequitur here.

              Same for longer processed broader claims (or – gasp – a chain of continuations is possible).

    2. 5.2

      This current % and increase in continuation applications is particularly surprising in view of the availability of requests for continued examination (RCE).
      Very different animals. From my experience, one does not file a continuation application unless it is for a very different set of claims and/or the parent application is allowed and you want make (significant or minor) tweaks to the claim language. Of those, the filing of a continuation after the allowance of the parent application is, by far, the most common.

      While one can go after broader claim language in a RCE, having an issued patent (albeit not perfect) and filing a continuation application with the broader claims is usually the preferred route.

      Furthermore, is not filing a separate later application for previously unclaimed subject matter in the original specification usually more appropriate for a divisional, rather than a continuation.
      No restriction = no divisional.

      Does this not suggest that a main motivation for filing continuations is for delay of issuance.
      No. From my experience, the main motivation is the expediting of issuance of allowable claims. BTW — one does not need to file a continuation to delay issuance.

      If the PTO would treat continuations as continuations, that is, in their originally claimed filing date.
      I’m not sure what you mean by that.

  5. 4

    Strange definition of an omnibus application, as it implies that the two inventions are unrelated. In my experience, the multiple inventions are generally related to various degrees. Sometimes an omnibus application (“kitchen sink application”) is forced on the drafter simply to meet the best mode and enablement requirements. In other cases, the relationship between inventions is such that the interrelationships are themselves patentable inventions.

    For instance, I had to draft an omnibus application that included Method A, Physical Product A made using Method A, Method B, Physical Product B made using Method B, and Method C, along with Physical Product C made using Method C. There was also the combination of Physical Product AB, Physical Product BC, Physical Product AC, and Physical Product ABC.

    The client agreed with me that it was better to file an omnibus application with multiple claim sets knowing that it would result in divisional applications rather than start with one claim set and then file continuations.

    As you can imagine, the restriction requirement was all botched up, and I had to explain the above (the A, B, C’s, as it were) to the Examiner in my response.

  6. 3

    So long as the courts can keep changing what my claims mean, I need to keep a continuation alive to be able to adjust accordingly where possible. (It’s really just about the last advantage patentees even have these days.)

    1. 3.1

      Ken, thanks for this candid comment, which encouraged my comment 5 above re other reasons to keep a continuation pending and add or amended claims, and why that is possible in the U.S..

      1. 3.1.1

        Your negativity in post 5 cannot be made up by your “politeness” here.

        Such comes across as more snide and less sincere. Ken’s point is pro-patentee, whereas I cannot recall a bottom-line pro-patentee statement from you like in forever.

  7. 1

    Hi Kate and Thomas,

    Thanks for the great post. Your post touches upon the part that’s a kind of enigma for many IP strategists – to go with drafting new claims or to go with tweaking some claims – when they consider filing a continuation application.

    What I think is before going for continuation filing, the party should assert the number of times they will be going foe continuation filing. And on that basis, they can decide whether tweaking claims work fine with them or whether drafting new claims.


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