Skip over navigation

904    How to Search [R-08.2012]

The examiner, after having obtained a thorough understanding of the invention disclosed and claimed in the nonprovisional application, then searches the prior art as disclosed in patents and other published documents, i.e., nonpatent literature (NPL). Any document used in the rejection of a claim is called a reference. An inventor name search should be made to identify other applications and/or patents which may be applicable as references for double patenting rejections. See MPEP § 804.

In all continuing applications, the parent applications should be reviewed by the examiner for pertinent prior art. Where the cited prior art of a parent application has been reviewed, this fact should be made of record in accordance with the procedure set forth at paragraph II.(E) of MPEP § 719.05. For national stage applications filed under 35 U.S.C. 371, the examiner will consider the documents cited in an international search report when the Form PCT/DO/EO/903 indicates that both the international search report and the copies of the documents are present in the national stage application file. See MPEP § 609.03.

The first search should be such that the examiner need not ordinarily make a second search of the prior art, unless necessitated by amendments to the claims by the applicant in the first reply, except to check to determine whether any reference which would appear to be substantially more pertinent than the prior art cited in the first Office action has become available subsequent to the initial prior art search. The first search should cover the invention as described and claimed, including the inventive concepts toward which the claims appear to be directed. It should not be extended merely to add immaterial variants.

In the first action on the merits of an application, the examiner must complete the Image File Wrapper (IFW) search notes form in the Office Action Correspondence Subsystem (OACS) to include the classes and subclasses of domestic and foreign patents, abstract collections, and publications in which the search for prior art was made. Other information collections and sources in which the search for prior art was made must also be identified by the examiner. The examiner must also indicate the date(s) on which the search was conducted. Note MPEP § 719.05.

In subsequent actions, where the search is brought up-to-date and/or where a further search is made, the examiner must indicate on the IFW search notes form that the search has been updated and/or identify the additional field of search. See MPEP § 719.05. Any search updates should include all of the relevant or pertinent databases and the search queries and classifications employed in the original search.

904.01   Analysis of Claims [R-08.2012]

The breadth of the claims in the application should always be carefully noted; that is, the examiner should be fully aware of what the claims do not call for, as well as what they do require. During patent examination, the claims are given the broadest reasonable interpretation consistent with the specification. See In re Morris, 127 F.3d 1048, 44 USPQ2d 1023 (Fed. Cir. 1997). See MPEP § 2111 - § 2116.01 for case law pertinent to claim analysis.

904.01(a)   Variant Embodiments Within Scope of Claim

Substantially, every claim includes within its breadth or scope one or more variant embodiments that are not disclosed in the application, but which would anticipate the claimed invention if found in a reference. The claim must be so analyzed and any such variant encountered during the search should be recognized.

In each type of subject matter capable of such treatment (e.g., a machine or other apparatus), the subject matter as defined by the claim may be sketched or diagrammed in order to clearly delineate the limitations of the claim. Two or more sketches, each of which is as divergent from the particular disclosure as is permitted by claim recitation, will assist the examiner in determining the claim’s actual breadth or scope. However, an applicant will not be required to submit such sketches of claim structure. In re Application filed November 16, 1945, 89 USPQ 280, 1951 C.D. 1, 646 O.G. 5 (Comm’r Pat. 1951).

904.01(b)   Equivalents

All subject matter that is the equivalent of the subject matter as defined in the claim, even though specifically different from the definition in the claim, must be considered unless expressly excluded by the claimed subject matter. See MPEP § 2181 - § 2184 for a discussion of equivalents when a claim employs means or step plus function terminology.

904.01(c)   Analogous Arts

Not only must the art be searched within which the invention claimed is classifiable, but also all analogous arts must be searched regardless of where the claimed invention is classified.

The determination of what arts are analogous to a particular claimed invention is at times difficult. It depends upon the necessary essential function or utility of the subject matter covered by the claims, and not upon what it is called by the applicant.

For example, for search purposes, a tea mixer and a concrete mixer may both be regarded as relating to the mixing art, this being the necessary function of each. Similarly a brick-cutting machine and a biscuit cutting machine may be considered as having the same necessary function. See MPEP § 2141.01(a) for a discussion of analogous and nonanalogous art in the context of establishing a prima facie case of obviousness under 35 U.S.C. 103. See MPEP § 2131.05 for a discussion of analogous and nonanalogous art in the context of 35 U.S.C. 102.

904.02   General Search Guidelines [R-08.2012]

In the examination of an application for patent, an examiner must conduct a thorough search of the prior art. Planning a thorough search of the prior art requires three distinct steps by the examiner: (A) identifying the field of search; (B) selecting the proper tool(s) to perform the search; and (C) determining the appropriate search strategy for each search tool selected. Each step is critical for a complete and thorough search.

When determining the field of search, three reference sources must be considered - domestic patents (including patent application publications), foreign patent documents, and nonpatent literature (NPL). None of these sources can be eliminated from the search unless the examiner has and can justify a reasonable certainty that no references, more pertinent than those already identified, are likely to be found in the source(s) eliminated. The search should cover the claimed subject matter and should also cover the disclosed features which might reasonably be expected to be claimed. The field of search should be prioritized, starting with the area(s) where the invention would most likely be found in the prior art.

Having determined the field of search, the examiner should then determine what search tools should be employed in conducting the search. Examiners are provided access to a wide variety of both manual and automated search tools. Choice of search tools is a key factor in ensuring that the most relevant prior art is found during the search. The choice of search tools to be used is based on the examiner’s knowledge of the coverage, strengths and weaknesses of the available search tools that are appropriate for use in an examiner’s assigned art. For example, a search tool may cover foreign patent documents; but, if that coverage does not meet the examiner’s current search needs, this should be taken into consideration by the examiner who will take recourse to employ other search tools in order to remedy the deficiency.

Search tool knowledge is particularly important for examiners in arts (e.g., very active, high technology) where patent documents may seriously lag invention and, consequently, represent a reference source of limited value. These examiners must take special care to ensure that their searches include consideration of NPL and employ the effective use of tools specialized to cover NPL pertinent to their search needs.

Search needs in some technologies, e.g., chemical structures, DNA sequences, are very specialized and can only be met through additional use of specific search tools specially constructed and maintained to respond to those needs. These tools cover all three reference sources - domestic patents (including patent application publications), foreign patent documents, and NPL .

In recognition that there are many available NPL search tools and their use is often complex, examiners have been provided and are encouraged to use the services of trained professional on-line search personnel located in the Technology Centers (Information Technology Resource Person (ITRP)) and in the Scientific and Technical Information Center (STIC) for NPL searching. See MPEP § 901.06(a) for services available in STIC.

In crowded, highly developed arts where most claimed inventions are directed to improvements, patent documents, including patent application publications, may serve as the primary reference source. Search tool selection in such arts may focus heavily on those providing patent document coverage.

Automated search tools covering patent documents usually provide both a classified and text search capability. Text search can be powerful, especially where the art includes well-established terminology and the search need can be expressed with reasonable accuracy in textual terms. However, it is rare that a text search alone will constitute a thorough search of patent documents. Some combination of text search with other criteria, in particular classification, would be a normal expectation in most technologies.

Examiners will recognize that it is sometimes difficult to express search needs accurately in textual terms. This occurs often, though not exclusively, in mechanical arts where, for example, spatial relationships or shapes of mechanical components constitute important aspects of the claimed invention. In such situations, text searching can still be useful by employing broader text terms, with or without classification parameters. The traditional method of browsing all patent documents in one or more classifications will continue to be an important part of the search strategy when it is difficult to express search needs in textual terms.

Having determined what search tool(s) should be used to conduct the search, the examiner should then determine the appropriate search strategy for each search tool selected. The appropriate search strategy should be determined by the examiner on a case-by-case basis along with consultation with other examiners, supervisory patent examiners, and/or trained professional on-line search personnel, where appropriate.

In order for examiners to acquire specialized skills needed to determine an appropriate field of search in their specific arts, each Technology Center may develop supplemental specific guidance and training for its examiners. This training will augment general training and information on search tools that is normally provided through the Office of Patent Training and Search and Information Resources Administration.

904.02(a)   Classified Search

A proper field of search normally includes the subclass in which the claimed subject matter of an application would be properly classified. It is not necessary to search areas in which it could reasonably have been determined that there was a low probability of finding the best reference(s).

In outlining a field of search, the examiner should note every class and subclass under the U.S. Patent Classification system and other organized systems of literature that may have material pertinent to the subject matter as claimed. Every subclass, digest, and cross-reference art collection pertinent to each type of invention claimed should be included, from the largest combination through the various subcombinations to the most elementary part. The field of search should extend to all probable areas relevant to the claimed subject matter and should cover the disclosed features which might reasonably be expected to be claimed. The examiner should consult with other examiners and/or supervisory patent examiners, especially with regard to applications covering subject matter unfamiliar to the examiner.

The areas to be searched should be prioritized so that the most likely areas of finding relevant prior art are searched first.

904.02(b)   Search Tool Selection

Detailed guidance on the choice and use of specific search tools can be established only within the context of the special requirements of each Technology Center (TC). However, a general methodology following a “decision tree” process, set forth below, for making broad decisions in search tool selection is suggested.

search Tool Selection Chart

904.02(c)   Internet Searching

The Office published a Patent Internet Usage Policy to establish a policy for use of the Internet by the Patent Examining Corps and other organizations within the USPTO. See Internet Usage Policy, 64 F.R. 33056 (June 21, 1999). The Articles of the Patent Internet Usage Policy pertinent to Internet searching and documenting search strategies are reproduced below. Note that a reissue application, a reexamination proceeding, and an application that has been published pursuant to 35 U.S.C. 122(b) need not be kept in confidence; therefore, the restriction on the search queries used when performing an Internet search referenced in Article 9 below would not apply to these applications and proceedings. USPTO personnel may use the Internet to search, browse, or retrieve information relating to the claimed invention(s) of a published application, a reissue application, or a reexamination proceeding. See MPEP § 707.05(e) for information pertaining to the citation of electronic documents and MPEP § 502.03 for information pertaining to communications via electronic mail.


The ultimate responsibility for formulating individual search strategies lies with individual Patent Examiners, Scientific and Technical Information Center (STIC) staff, and anyone charged with protecting proprietary application data. When the Internet is used to search, browse, or retrieve information relating to a patent application which has not been published, other than a reissue application or reexamination proceeding, Patent Organization users MUST restrict search queries to the general state of the art unless the Office has established a secure link over the Internet with a specific vendor to maintain the confidentiality of the unpublished patent application. Non-secure Internet search, browse, or retrieval activities that could disclose proprietary information directed to a specific application which has not been published, other than a reissue application or reexamination proceeding, are NOT permitted.

This policy also applies to use of the Internet as a communications medium for connecting to commercial database providers.


All Patent Organization users of the Internet for patent application searches shall document their search strategies in accordance with established practices and procedures as set forth in MPEP § 719.05 II.(F).

904.03   Conducting the Search [R-08.2012]

It is a prerequisite to a speedy and just determination of the issues involved in the examination of an application that a careful and comprehensive search, commensurate with the limitations appearing in the most detailed claims in the case, be made in preparing the first action on the merits so that the second action on the merits can be made final or the application allowed with no further searching other than to update the original search. It is normally not enough that references be selected to meet only the terms of the claims alone, especially if only broad claims are presented; but the search should, insofar as possible, also cover all subject matter which the examiner reasonably anticipates might be incorporated into applicant’s amendment. Applicants can facilitate a complete search by including, at the time of filing, claims varying from the broadest to which they believe they are entitled to the most detailed that they would be willing to accept.

In doing a complete search, the examiner should find and cite references that, while not needed for treating the claims, would be useful for forestalling the presentation of claims to other subject matter regarded by applicant as his or her invention, by showing that this other subject matter is old or obvious.

In selecting the references to be cited, the examiner should carefully compare the references with one another and with the applicant’s disclosure to avoid the citation of an unnecessary number. The examiner is not called upon to cite all references that may be available, but only the “best.” (37 CFR 1.104(c).) Multiplying references, any one of which is as good as, but no better than, the others, adds to the burden and cost of prosecution and should therefore be avoided. The examiner must fully consider all the prior art references cited in the application, including those cited by the applicant in a properly submitted Information Disclosure Statement.

The best reference should always be the one used. Sometimes the best reference will have a publication date less than a year prior to the application filing date, hence it will be open to being overcome under 37 CFR 1.131. In these cases, if a second reference exists which cannot be so overcome and which, though inferior, is an adequate basis for rejection, the claims should be additionally rejected thereon.

In all references considered, including nonpatent, foreign patents, and domestic patents, the examiner should study the specification or description sufficiently to determine the full value of the reference disclosure relative to the claimed or claimable subject matter.



United States Patent and Trademark Office
This page is owned by Patents.
Last Modified: 03/27/2014 10:10:36