Patents Q&A

How Should I Respond to a Restriction Requirement?


Patent examiners may issue a restriction requirement against a pending patent application. Restriction is permitted under U.S. patent law if two or more independent and distinct inventions are claimed in one patent application. Knowing how to respond to a restriction requirement, and what types of responses are possible, first requires understanding what they are. There are some strategic and practical considerations that make some types of responses more worthwhile than others. What makes the most sense will depend on the particular claims involved, the basis of the restriction, and the application’s patenting strategy. Experienced U.S. patent attorneys tend to have a sense or intuition about what sorts of restriction requirements are proper and which sorts of responses are worthwhile in any given case.

Restriction practice centers around how much work the USPTO has to do to examine a given application. Applicants are sometimes frustrated by restriction requirements that have the appearance of an examiner trying to avoid work or to game the “count” system that is used internally by the USPTO to track examiner productivity, by forcing the applicant to file a divisional application. At times, the rationales given for restrictions can seem unconvincing or circular. On the other hand, applicants seeking to avoid the official fees normally associated with filing separate patent applications for independent and distinct inventions that necessitate separate examination are rightfully subject to restriction requirements.

The Basics of a Restriction Requirement

A conventional restriction requirement means the examiner believes there are multiple independent or distinct inventions being claimed. A restriction requirement will identify different inventions by groups of claims. The examiner is insisting that the applicant pick one claimed invention, by group, to be substantively examined for patentability. That is called making an election.

Every requirement to restrict has two aspects: (A) the reasons why each invention as claimed is either independent or distinct from the other(s); and (B) the reasons why there would be a serious burden on the examiner if restriction was not required.

Claims are “independent” if there is no disclosed relationship between the inventions, that is, they are unconnected in design, operation, and effect. This type of restriction is straightforward. It does not come up that often.

Restrictions between related but “distinct” inventions are more common. These restrictions are closely tied to prohibitions against double patenting. The precise requirements for a proper distinctness restriction will depend on the types of claims involved. A lower standard applies to restrict out inventions in different statutory categories—generally referring to the difference between apparatus and method/process claims. However, for applications with so-called combination and subcombination claims (e.g., claims to an overall device and to a subassembly usable in it), or with claims to related products or related processes (i.e., claims in the same statutory category), a higher standard is applied. Further, even when claims are distinct, the examiner must also show that examining those claims together would pose a serious burden. This refers to the burden to search for prior art and evaluate the claimed invention against the search results.

Where the claims of an application define the same essential characteristics of a single disclosed embodiment of an invention, restriction between them should never be required. This is because the claims are not directed to distinct inventions. Rather, they are simply different definitions of the same disclosed subject matter, merely varying in breadth or scope of definition. Many if not most patent applications do disclose multiple embodiments, which can raise questions about whether particular claims are directed to the same or different embodiments.

Examiners have considerable discretion about issuing restriction requirements. Even when a restriction requirement could be made, an examiner is not affirmatively required to do so. There is considerable variation in how restriction practice is utilized by different examiners, and also between different technology centers and group art units at the USPTO.

Following a restriction requirement, the applicant is required to elect one group of claim(s) for examination. Unelected (or nonelected) claims will be withdrawn and will not be substantively examined. Importantly, an applicant will generally be prohibited from later adding claims to an invention independent or distinct from the elected claims. There is generally no opportunity to change your election later on. Although “rejoinder” may permit previously unelected claims to be allowed if they depend from or otherwise require all the limitations of an allowable claim. Rejoinder is discussed further below.

Unelected claims can remain in an application, denoted as “withdrawn”. Examiners essentially ignore withdrawn claims. It is possible to amend withdrawn claims if desired. However, withdrawn claims must either be rejoined or canceled when an application is in condition for allowance. If the elected claims are patentable, it is common for patent examiners to call counsel of record to request approval of an examiner’s amendment to cancel withdrawn claims, in order to permit a notice of allowance to be sent. If restriction was not traversed, examiners can also unilaterally cancel withdrawn claims at allowance by way of an examiner’s amendment.

Election of species requirements are related to but distinct from basic restriction requirements among groups of claims. Considerations for election requirements are discussed elsewhere. If present, they require a separate and distinct response by the applicant in addition to a responsive election of a group of claims.

PCT National Phase Entry Applications

Regular restriction practice does not apply to PCT national phase entry applications. Instead, a unity of invention standard governs, which requires having a common or corresponding special technical feature that defines a contribution over the prior art. However, U.S. examiners can still issue requirements to elect a particular invention in national phase applications and withdraw unelected claims and the procedures are similar. Applicants must still make elections and rejoinder of withdrawn claims is still possible. This means that the ultimate effects are similar though the terminology differs somewhat. If anything, there is slightly greater leeway for applicants to amend the claims to keep them together under the unity of invention standard.

If a U.S. examiner applies conventional restriction practice requirements to PCT national phase entry applications, that is a procedural error that should be called to the examiner’s attention. That sort of mistake does happen from time to time.

However, it is important to note that prior indications by the international search authority or international preliminary examining authority in the international phase of a PCT application are not binding in the national phase. That means that even if a prior PCT written opinion indicated that claims posses unity of invention, the U.S. examiner could disagree and still issue a unity of invention restriction in the national phase.

Requirements for Replying to a Restriction Requirement

Patent applicants are required to elect a claim group for examination in reply to a restriction requirement. A reply (or response) is considered incomplete if no election is made.

An election can be either “with traverse” or “without traverse”. “Traverse” means that the applicant is arguing that the restriction requirement is incorrect or improper and should be reconsidered and withdrawn in whole or part. An election of claims made with traverse is called a provisional election. Traversing a restriction requires actually making an argument about why the restriction requirement is wrong. Simply saying “with traverse” without making a substantive argument will be treated as an election without traverse.

Once restriction is required, a nonelected claim is only “withdrawn” once the examiner withdraws it from consideration. When initially responding to a restriction requirement, the examiner has not yet withdrawn any claims (and has not considered any traversal arguments). So when reproducing the claims in a restriction reply, such as to make claim amendments, the “withdrawn” identifier should not yet be used. But in any subsequent amendments, following the examiner’s indication that claims are withdrawn in an office action, the withdrawn claims withdrawn must be indicated as “withdrawn”.

Strategic Considerations for Restriction Responses

There are a few strategic considerations the go into deciding how to reply to a restriction requirement. Consider the following, for example:

  1. What is the most commercially important aspect of the invention, and which group of claim(s) best covers that aspect? Many times this is the most important consideration.
  2. How many claims are in each group (i.e., which group contains more claims)? Sometimes electing a group with more or the most claims might provide better value, in the sense of having a larger number of existing claims examined. Although the elected group of claims could potentially be expanded by adding new claims and/or amending existing claims.
  3. Is the restriction between apparatus and method/process claims? Elections in this situation raise special considerations that sometimes make election of apparatus claims more desirable. If the apparatus claims are elected, rejoinder of the unelected claims to a method of making and/or using the product might be later rejoined and granted. However, if the method/process claims are elected, then rejoinder of the apparatus claims is not permitted.
  4. Might claims be amended? One or more independent claims might be amended to recite a common essential inventive feature as part of a traversal argument to try to make the restriction moot. Alternatively, or additionally, new claims might be added, such as by canceling unelected claims and adding new dependent claims to the elected group (canceling unelected claims may avoid official extra claim fees in this scenario). Unelected, withdrawn claims can also potentially be amended later, to try to facilitate rejoinder. However, claim amendments might have prosecution history estoppel implications and claim amendments cannot have the effect of contradicting a prior election.
  5. Are you willing to file one or more divisional application(s) to pursue unelected claims? A restriction requirement is an indication that filing unelected claims in a new divisional application will prohibit a double patenting rejection in the later-filed divisional. However, whether or not the applicant is willing to incur further expense associated with a divisional filing (or perhaps multiple divisionals) may influence which claims are elected in response to the restriction. It is possible to defer a divisional filing decision so long as the current application remains pending. This may allow an opportunity for claim rejoinder to be considered. Ensure that there is a clear demarcation between restricted claims to preserve divisional filing safe harbor protections against double patenting, particularly if an election of species is involved. Keep in mind both short-term (e.g., costs to traverse and/or petition a restriction) and long-term costs (e.g., divisional filing and maintenance fees) associated with each option.
  6. Which group(s) of claims have the best chance of patentability? This may not be known. But, depending on the scope of the prior art or potential patent-eligibility issues, certain groups of claims might face easier or more difficult examinations. If the restriction requirement cites prior art as justification for restriction, that cited art may inform how to make a claim election. If the restriction alludes to prior art without specifically citing any references, it may be possible to call the examiner to obtain further information about the particular prior art that the examiner has in mind.
  7. Did you intend different claims to cover different inventions, or simply want different claims to have distinct scope? In some situations, the claims may have been originally drafted to purposefully have significantly different scope. In that case, traversing the restriction might be contrary to an existing patenting strategy.
  8. Is it important to obtain a patent very quickly, or not? Certain elections or traversals of restriction may make examination take longer, such as if they result in an application being reassigned to a different examiner in a different group art unit. However, the effect on the speed of examination may be speculative at the time of the claim election.
  9. Has the examiner made a procedural error or omission in the restriction? For instance, the MPEP says, “Examiners must provide reasons and/or examples to support conclusions . . . .” As another example, an examiner might list nonexistent or inapplicable search classifications. Moreover, examiners may state grounds for restriction that are contrary to statutory, regulatory, or MPEP provisions. Examiners might apply domestic restriction practice to a PCT national phase entry application where unity of invention instead applies, for example.

Sometimes it is not worthwhile to challenge a questionable restriction by traversing it. Doing so requires effort. It may be more expedient and cost-effective to pursue other options, such as by amending claims and/or by cancelling claims and filing them in a new divisional application. Examiners often maintain rejections regardless of any traversal arguments, and will simply adjust the stated rationale slightly. Patent attorneys sometimes consider traversing a restriction to be a waste of time. Though if an examiner has made a substantial mistake by overlooking or misstating claim language, for instance, traversal may be worthwhile. Also, traversal is necessary to preserve the right to later petition against the restriction.

Design patent applications with multiple claimed embodiments also present unique questions with regard to the effect of an election on the doctrine of equivalents, because the concepts of literal infringement and equivalents infringement are intertwined for design patents.

An experienced patent attorney can help an applicant assess possible restriction response strategies for any given case.

Petitions Against Restriction Requirements

It is possible to file a petition against a restriction that has been made final. Such petitions are decided by technology center directors, as opposed to the Office of Petitions or some other centralized USPTO authority. However, such petitions may not be worth the effort and cost in attorney fees—unless, for instance, the applicant faces a need for multiple divisionals with a large total cost. Importantly, such a petition against a restriction may be deferred until after final action on or allowance of claims to the invention elected, but must be filed not later than an appeal.

In order to preserve the ability to file a petition against a restriction, it is necessary to traverse the restriction in the initial response. Failing to traverse a restriction waives the opportunity to later file a petition against that restriction.


Unelected, withdrawn claims can potentially be rejoined upon the allowance of an elected claim. Claims that depend from or otherwise require all the limitations of an allowable claim are eligible for rejoinder. Rejoinder is also possible when there is a “linking claim”. Rejoinder practice means that unelected claims might still have a chance to be included in a granted patent despite a prior restriction.

What is unintuitive about rejoinder practice, however, is that when a restriction is between product/apparatus claims and claims to a method of making and/or using the product, rejoinder is only possible if the product or apparatus claims are elected. Election of the method claims will not allow later rejoinder of the unelected product/apparatus claims. This means withdrawn method claims might be keep in the application for possible later rejoinder but, when method claims are elected, withdrawn apparatus claims might instead be cancelled at an appropriate time. This is a somewhat arbitrary aspect of USPTO procedure, but nonetheless needs to be considered at the time an election is made.

Photo of Austen Zuege

Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.