The Frequency of Means-Plus-Function Claims

The chart above shows the continued decline in the use means-plus-function claim limitations in U.S. Patents. To create the chart, I identified a sample of patents for each year and then used an automated search query to count the percent of patents that use the phrase "means for" in the claim set. This chart is even more dramatic if you consider that the average number of claims-per-patent has dramatically increased during this same period.

49 thoughts on “The Frequency of Means-Plus-Function Claims

  1. 49

    Red Monkey M+F claims are not only easy to draft, they sound broader than they really are. This tends to cause discomfort to a competitor. Although they are limited to the disclosed embodiments and equivalents thereof, they nevertheless inject enough uncertainty to motivate one to license.

    This sort of “strategy” really applies only to “technologies” where one’s competitors are clueless about patent law.

  2. 48

    I also paid the fees for my first Patent to print. I also paid the maintenance Fees for the first Maintenance Fee charge. It was never a Patent! I paid for the next one to Issue. It too was never Patented because it was purposely messed with so they could infringe it legally too. Also My fees were paid for My Trademark. As a matter of fact I was paying over and over when it was abandoned and I never knew it had been until this past Year. So if there is a question of whether I am paid UP! Truly I am!

  3. 47

    FDCPA I bought some Carpeting from a Company. The man I dealt with charged me for so many feet of a 12 ft wide carpet instead of approx. 1200 square feet. I called the BBB. They made him settle with what was clearly fraudulent practices. While I was dealing with more of the same, I was constantly called over and over by this Company years after he was forced to settle, when it is clearly of record at the BBB that they settled.I know this was a sham phone call and just more pressure added. I think this was put in my Bankruptcy as a debt AGAIN along with other fraudulent charges thanks for the INFO.

  4. 46

    If you say so Ned. When the only novelty is a M+F feature, that claim might well not survive an ordinary assault on its validity, that on the preponderance of evidence it embraces obvious subject matter.

    When finding a claim obvious is so easy to do, here in Europe, the court is relieved of an awkward duty to do violence to the plain and ordinary meaning of the claim, just to get to a just result.

    You will gather that I am not a fan of courts indulging in creative distortion of the plain wording of the claim, just to get to the “right” result.

  5. 45

    Max, if a MPF element is at the point of novelty, and if the claim is not construed in the manner of 112, p. 6, it is necessarily too broad. What this suggests to me is that the courts are in fact construing the claims narrowly.

  6. 44

    In the EPO, these past 30 years, there are two sorts of insufficiency, just like in the UK. The claim is bad if the specification does not enable over the full scope of the claim.

    As a practical matter though, despite revocation hanging on a mere preponderance of the evidence, it is almost invariably too hard to succeed with that attack. It has always been there though, available for those situations when it is needed.

  7. 43

    See my post below to Paul, but I think the assumption that one can claim in Europe or for that matter anywhere all means for achieving a result and have that claim be enforced against independent inventions of others that take nothing from the teaching of the specification is naive.

    See, link to

  8. 42

    Paul, if I read the linked article correctly, Biogen is not yet well established law throughout Europe.

    See, link to

    However, the article does suggest to me that the assumption that one can claim all means for achieving a result when disclosing only one, enabling only some equivalents, and expect such a claim will be enforceable for the full scope claimed is naive. Such a claim will be met, at least in the UK, with a finding of “insufficiency” to the extent that such a claim were construed for the full breadth claimed.

    This does, suggest, does it not, that the rule of 112, 6, should be the law in Europe, assuming sufficiency will gain traction in Europe as it appears to have in the UK?

  9. 41

    Under European practice, if the invention is in the discovery of the problem then a broad functional claim may be supportable. However, if the invention is the discovery of a solution to a known problem it is more likely that a narrower and possibly structural claim will be needed. The decision of the House of Lords in Biogen cited O’Reilly v Morse in this connection.

    The underlying problem is over-speculation and claiming more than has been invented, therefore stifling legitimate research. That is really what troubled the Halliburton court, and over here Robin Jacob was well aware of the problem and astute to protect the rights of researchers.

  10. 40

    @Bob. I completely agree that if a specification is to have means + function claims, then the foreigh practitioner should be aware of US requirements for such claims to be valid and should comply with thise requirements.

  11. 39

    Regret, Ned, the USA can’t “sign up” because Art 166 EPC (“Accession”) limits to “any other European” State, and we know that the USA is not ready yet to become a European State.

    There was a move, a few years ago, to delete “European” from the text of Art 166 but nothing came of it. Insufficient enthusiasm for it, I suppose.

    I should have added to my earlier note that the EPO has a tie-breaker called the Enlarged Board of Appeal (EBA), that swings in to operation when there is stalemate between two rival legal theories promoted by different EPO Boards of Appeal. So the EBA is the capstone on the consensus development of EPC law.

    That eminent English patents judge Robin Jacob put it nicely, on the way the Supreme Court of an EPC Member State should relate to the EPO EBA. The captain of the ship should obey the Commodore of the Fleet, unless the commodore is leading the fleet onto the rocks.

    Still want to sign up? To that? Surely not.

  12. 37

    I think you just suggested that we Americans should consider abolishing the US Supreme Court?


    But you do raise a good point.  1000 cases per year does give a rich and deep source of "guidance" that increases predictability.  I like the notion, indeed.

    How do we sign up?

    And, wouldn't it have been nice if we had signed up in our consideration of FTF?

  13. 36

    Well Palmer has covered your questions mostly so I’ll just add a bit about the EPO.

    It was in the context of the EPO that I mentioned “commensurate”. The EPO doesn’t do infringement cases.

    There are at least 24 Technical Boards of Appeal at the EPO. If one of those accedes to a request from the Opponent, and revokes your client’s patent Ned, that’s the end of the line for the patent owner, in up to 42 European countries, and for 600 million consumers. By this I mean you can’t appeal any further.

    Now, who tells those TBA’s how to decide their cases?

    Nobody. But collectively they decide well over a thousand validity cases per year. This helps them to decide wisely. It’s a sort of Darwinian progess of the patent jurisprudence at the EPO, free from the meddling of any superior court populated by non-patent-specialist judges. A bit different from KSR and Bilski, eh Ned?

    And that is why competent and experienced professionals in Europe can, with a high degree of confidence, opine on the ultimate validity of any searched claim pending at the EPO.

  14. 35

    Alun, thanks much for you very informative post.

    I live in Kalifornia, a state born from the Spanish Empire via a cash purchase from Mexico. We are nominally a Roman Law state. So, when a court decides an issue of law for the first time, particularly of statutory construction, we update the statutes. So, all you really have to do is look at the code book to see what the law is.

    That said, we still look at cases for “guidance.”

  15. 34

    You did indeed get the system of binding precedent from England, although oddly perhaps from your point of view, I’ve never seen an English court call it stare decisis, which, although Latin, seems to be purely American(?!).

    It does seem to be applied somewhat differently though, as Americans talk of a holding in a case, and seem to apply the decision itself to other cases, as best as I can explain it. In England, OTOH, what is done is to determine the ratio (Latin for the French word rationale that one uses outside of legal matters) of the case, i.e. the principle on which the decision was decided, and then apply that principle, or ratio, and not simply the decision itself, to other cases. The difference is subtle, but I am not convinced that it is the same thing with different labels, although very nearly so.

    But then I am not actually a lawyer (although some have said that I ought to be). I am a US patent agent who happens to be English.

    Max was talking about


    Europe, of which the UK is not part, due to the ten miles of water between Dover and Calais. Their law is based on Roman civil law, which does not recognise precedent, at least in theory (never mind the tendency of courts to determine similar cases in a similar way).

    Even the English common law system owes something to Roman law, but it has been said that the system of precedent began because the roll of the codified law had been physically lost!

    A distinction must be made between different parts of the UK also, as some of them, such as Scotland, also follow the civil law system. It is interesting what happens when a Scottish case goes to the House of Lords, and precedent is applied there for the first time in the case, but I’m sure something similar must occur with Louisiana for the same reason.

  16. 33

    Bill, I think the Feds have gone out of their way — way, way out of their way in fact — to limit 112, p. 6 to uses that have both the magic words and no “structure” that can carry out the function.

  17. 32

    Re: binding precedent, I thought we got that from you guys in England. Common law. Stare Decisis.

    Now, if that is not the case, what is the use of having a boss court unless the slave courts obeyed?

    On scope, “who” decides whether the scope claimed exceeds the contribution when, years after the patent issues, an infringement suit is brought against one who is not using anything disclosed or enabled in the specification, yet whose activities fall within the literal construction of the claims?


  18. 31

    I can see it going both ways. Defendant could say if he had meant one means, why did he use the plural? After all, he had years at the PTO to amend the claim. Plaintiff could say that all his embodiments disclose one means. Who knows? But just the fact the issue is even questionable is bad for plaintiff.

  19. 30

    Would it be “unreasonable” to interpret such a claim to require two or more “meanses”?

  20. 28

    “Why should anybody write in a claim that the means “comprise”?”

    It’s another million dollar issue.

  21. 27

    In that case, Monkey, doesn’t everybody parse “means” as singular? Why should anybody write in a claim that the means “comprise”?

  22. 25

    Can’t be bothered, Ned, with thinking about Selden. Might be better to tune in to the more topical debate about reach-through claims in biotech. Who was the guy who patented the research tool and then sued the entire pharma industry.

    There is rich European jurisprudence about sufficiency, obviousness and width of claims. A touchstone of EPO jurisprudence is that the scope of protection shall be commensurate with the scope of the contribution to the art. Whether one worked Example in the specification is enough depends on the facts of the case. Just recently, we are mining a rich seam of cases on the issue how much one can speculate, in the application as filed, without crashing on the utility issue.

    In mainland Eirope we have no Binding Precedent Ned. So we make it up as we go along. Yours is the jurisdiction which lectures us all the time that, for Legal Certainty, you have to have Binding Precedent. Permit me to raise a quizzical eyebrow on that one.

  23. 24

    Monkey, somebody once told me that, in US patent litigation, every “issue” puts another million dollars on the cost, so one must make every effort to keep the number of “issues” to a minimum. I see that whether “comprise” has a second “s” is one such issue. Point taken. One can never worry enough, in this game.

    Is there anything in the US legislative corpus corresponding to the UK Interpretation Act of 1883, which prescribes that, in any written instrument, the singular includes the plural and the plural includes the singular, unless the context dictates otherwise?

  24. 23

    M+F claims are not only easy to draft, they sound broader than they really are. This tends to cause discomfort to a competitor. Although they are limited to the disclosed embodiments and equivalents thereof, they nevertheless inject enough uncertainty to motivate one to license. Given the ease of drafting and the uncertainty that can only benefit the plaintiff, it seems like a no brainer to include them. One can always delete them in other jurisdictions.

  25. 22

    Well, if a claim says “means for regulating a voltage, wherein said means comprise a transformer”, an accused infringer might say “My device only has one structure that carries out the recited function, and even though my one structure has a transformer, I only have one such structure.”

    If you had said “comprises” instead in the claim, this argument would be a bit harder to make.

  26. 21

    So, given the Selden case, you would not have allowed a claim to a gasoline-engine powered car based on a disclosure of one engine of a particular type? Gasoline engine means for powering a horseless carriage and all that?


  27. 20

    Can we get involved here? It has already told us not to write “Doctrine of Equivalence”. It would be nice if it could also tell us whether “means” is singular or plural. Can it be bothered though?

    How important is it, readers, that we know for sure which is correct, singualr or plural? How much hangs on it? I’m curious.

  28. 19

    On a related note, is a “means for doing X” singular or plural? Do you say, in a dependent claim, “wherein said means comprise” or “wherein said means comprises”?

  29. 18

    Ned, you know from the EPC the grounds of invalidity, for an issued claim in Europe. You know from Art 69 EPC and its Protocol what is the scope of protection given in Europe by an issued claim. You know that the burden to prove infringement is the preponderance and that the burden on the petitioner for revocation is also a preponderance standard.

    So, it’s symmetrical. And simple.

    Not so in the USA, where the C+C standard on validity messes everything up. Weird constructions are put on claims, a weird clause is inserted in the patent statute, and weird reasoning emerges from the courts, all because of the difficulties of calling out a bad “duly issued” claim as simply…invalid.

    But you, and others, are going to tell me, I know, that’s the price to pay, for a uniquely “strong” patent system.

    Perhaps you are right. I don’t know. Perhaps Paul Cole has a different view?

  30. 17

    Since when did it become acceptable for mainstream advertising in america to blend porn with sock ads for womenz?

    I want to note that this could be NOT SAFE FOR WORK IN THE US.

    Apparently in Europe, at least if Modern Family is correct, topless womenz are in advertisements like all the time.

    link to

    Note the middle ad top row. I got to this page directly from youtube where a barely dressed young asian lass was beckoning me in.

    I just don’t understand, has the revolution finally come to America and washed away all our morals?

    Also funny is the vid I was watching.

    link to

    link to

    You should be able to see the asian chic in the second one. Tell me you wouldn’t “click on” that.

  31. 16

    Interesting comments above. I’d say this chart strongly suggests that MPF claiming has declined, as long as we assume that when people want to invoke 112(6) they usually use the magic words. We’d also have to assume that “step for” language has not gone proportionally up. These seem like safe assumptions to me, but it would also be interesting to view this beside a chart of federal-court rulings on whether 112(6) applies absent the magic words. If courts have gotten less strict in requiring the “means for” phrase, then maybe patent drafters are just getting comfortable drafting their MPF claims within a wider range of phrases.

  32. 15

    Fish sticks makes a good point. Perhaps the analysis didnt pick up on “means …for” with intervening terms. Lots of cases use these terms apparently to make up for a lack of appropriate vocabulary, but without using the exact language specifed in 112 6th. Its anyones guess in those cases whether claim drafters were trying to invoke the statute. Examiners have been instructed to reject more misuse of “means for” under 112 1st and 2nd in the last few years.

  33. 14

    If you write cases with m+f in the claims and file these in the U.S., you’re not doing us a favor. In fact, based on the cases I’ve seen that come from the EP, you’re creating invalid claims in the U.S. (e.g., “means for receiving” where there is no description whatsoever as to what this means might be). As for filing cases in different jurisdictions, often we’ll add complete sets of M+F claims to the specification (complete with multiple dependencies) so that these “claims” can be added in the EP. (Or we’ll add as complete claim sets with multiple dependent claims and cancel via preliminary amendment.)

  34. 13

    Max or Paul, on non infringement, look at the Selden patent litigation discussed here:

    link to

    Selden was perhaps the prototype troll. He submarined his patent, had minimal disclosure and broad functionally defined claims, and was able to hold up an entire industry. It took Henry Ford, who was denied a license by the “cartel” controlling the patent, to break it. The linked article says this:

    “Of the patent suit itself, Ford lost at trial, but established noninfringement on appeal.”

    “The engine disclosed by Selden was not an Otto engine:

    The logic of the Columbia opinion is not difficult to understand, even by the standards of 2001. The Selden patent disclosed a constant pressure engine, in which one had slow combustion without explosion. In contrast, Ford (and others) employed a constant volume engine, in which the piston moves by explosive action. n5 184 F. at 904. The engine of Selden required a constantly burning flame. 184 F. at 905. Of the doctrine of equivalents, the court seemed to cabin the scope because of the non-pioneering nature of the invention (“The patent as so construed necessarily permits only a very limited range of equivalent forms.” 184 F. at 911; “In giving weight to dissimilarities — in saying what are substantial and what relate merely to form — we must consider the degree of invention shown in the patent . . . ” 184 F. at 912.) One seems to have the rudiments of the Graver Tank tri-partite test: “[no equivalents] because the two engines do not perform the same functions in substantially the same way.” 184 F. at 915.”

    “See Resis, supra note 37, para. 11 (recounting the story of George Selden, the first recognized patent troll, who managed to submarine a “road engine” patent for 16 years while the auto industry blossomed).

    Ref 37 is Robert H. Resis, History of the Patent Troll and Lessons Learned, 17 INTELL. PROP. LITIG. 1, Winter 2006, para. 3 & n.5. ”

  35. 12

    M+F claims are incredibly easy to draft (hence their inherent popularity in certain circles) and I don’t see any reason not to include them in the summary section (or anywhere else), especially if the app is being filed internationally. We just don’t favor a strategy of pursuing them in the US, at least not as a first course of action.

  36. 11

    Max or Paul, does proof of infringement in Europe require proof that the accused subject matter be at least the equivalent of the disclosed subject matter? If not that, does it allow a defense that the accused subject matter is not the equivalent of the disclosed subject matter?

    Do you, in Europe, have any concept that the scope of infringement is limited by the scope of enablement? If one accomplishes the same result using substantially different means and methods, is one infringing even if the claim literally covers the accused device or process?

    Once upon a time, in reaction to the Federal Circuit’s clamping down on section 112, paragraph 6 equivalents and In re Donaldson, the AIPLA patent law committee voted to amend section 112, paragraph 6 to require that such claims be construed to cover all means for performing the recited function, and also at the same time to amend section 282, and the noninfringement defense, specifically to include the reverse doctrine of equivalents. I wonder if such an amendment would have brought US practice regarding means plus function claims into substantial alignment with the practice in Europe?

  37. 9

    Now I get you Paul thanks. And, yes, many US colleagues are averse to the idea of putting M+F claims in to the EPO. A situation I particularly enjoy is where their claim 1 bombs at the EPO and I then invite their attention to the statement of invention in their “Summary” section of their specification, being a clear and simple definition of the invention for which protection is being sought. What’s wrong with using that as claim 1, I ask. Incredulity is expressed. That won’t satisfy the Examiner, will it? Often it does.

  38. 8

    Perception very oftem matters more than reality (ask any journalist).

    Or better yet, ask any academic.

  39. 7

    If anything, this reinforces the belief that a select (but loud) few are busy shilling on a topic that is vastly overblown.

    Some will continue to chase the phantom bogeymen, seeing them in every shadow.

    How sad.

  40. 6

    European patent owned by US corporation. Claims issue in Europe in means + function form. Licensing deals with Chinese and Japanese corporations through US licensing counsel acting for the US company. Advice to potential licensees also through US counsel is that the European patent coverage is narrow. Nobody thinks to telephone the European attorney who prosecuted the case and ask him about it. License entered into but royalty rate cut because of perceived narrowness of the granted European patent.

    Not a pretty scenario! And if we put means + function claims to our US colleagues, they will not necessarily thik we are doing them a favour. Perception very oftem matters more than reality (ask any journalist).

  41. 5

    This is quite a bit off topic.You all play your games. But the end result will still be that the mind set of the People in this Economy has changed everything. Mark my own Pea Brained words. People are learning to buy everything used. This will effect the economy for many years to come. Remember my Flower People Generation. That was followed by the throw away Generation, as in everything from dresses to plates to cups, to people, you just threw them away. But times they are a changing says the Pea Brain that I am. This will effect every single Manufacturing Job in the USA. You had better sit down and get this mess fixed. You can’t fix what you have already done. But you can start the uphill battle to bring People back.

  42. 4

    Well thank you for that Paul, even though I’m not yet grasping what you are driving at, in your “If…..then…..” sentence.

    The “disadvantage” you say is suffered by the Applicant might not matter to you, but it does to me, as I prosecute through the EPO cases drafted in the USA.

  43. 3

    Max – it does not really matter. If our US, Chinese and Japanese colleagues think that means + function claims are of narrow scope, then licensing deals are likely to be done to the patentee’s disadvantage without the European attorney ever having the opportunity to explain what the true position is. And if you study the case law of the CAFC, you find many good ways around 35 USC 112(6).

    UK practitioners have for decades endeavoured to draft patent specifications for the world, not just for the UK. So if we know that means + function claims create problems in the US it makes sense to avoid them.

  44. 2

    The use of “means for” is all but gone, but not the use of functional language in claims.

    One wonders at times. Halliburton was not about means plus function clauses, but about functional claiming at the point of novelty — they are indefinite, according to the Supreme Court, regardless of the rule of construstion that they cover the corresponding structure and equivalents. Someday, these non means-plus-function functional expressions are going to be tested in court to see whether they are valid under Halliburton. Rich is no longer around to issue his oft-expressed opinion that Congress overruled Halliburton when it passed Section 112, p. 6. Frederico and Rich did not see eye-to-eye on that issue.

  45. 1

    Less than one in ten US patents currently issuing include those two little words “means for” anywhere at all, in the complete set of claims? Coming from the ROW, I’m astonished.

    I wonder, do American patent attorneys use the same sets of claims, unchanged, in their PCT filings, for achieving optimal coverage for their clients everywhere else in the world. Do they know (or care) that 112-6 has no counterpart anywhere else in the world. Readers?

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