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How to Perform Effective Prior Art Search (Part 1 of 3)

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August 7, 2017

This article is the first in a three-part series that provides some useful tips for performing prior art searches. These tips are based on best practices that we have relied on in the over 5,000 prior art searches we have delivered to companies worldwide.

Prior art search may seem like a tedious, unexciting task, but it demands skills requiring mental stamina, attention to details, ability to decipher sometimes incomprehensible writing, a sharp eye for recognizing patterns and clues, and the persistence of a bloodhound in search of its puppies in a vast, complex terrain. In some cases, deep and specialized technical knowledge will assume greater importance especially when the prior art search requires digging deeper into technically-complex subject matter, such as those behind many high-profile patent litigation. The prize for all those efforts and well-worn skills, would, of course, be those killer prior art on which the fate of either party in a patent litigation would likely depend.

Before conducting a prior art search, one needs to ask what the purpose of the search is. Is the prior art search for patent invalidation, preparation of patent application, or preparation for possible litigation? Depending on the reason, one would normally need to perform a significantly more comprehensive search for patent invalidation than, for example, for patent application preparation. On the other hand, when an invention that forms the subject matter of a patent application is considered quite valuable, the prior art search performed in those cases can sometimes rival the breadth of prior art search performed by some defendants in a patent litigation. For example, some patents, such as those owned by companies with deep technical and patent bench, sometimes include as many as 15 pages or more of cited references on each patent.

But whatever the reason behind a prior art search is, there are certain steps one can take to make it less daunting and more productive.

  • Focus on the “Inventive Concept”.
    1. A claim can sometimes have five or more limitations (i.e., elements or features). Thus, when the goal is to find a reference that anticipates a claimed invention (i.e., a reference that described the invention before the effective filing date of a patent application that issued into the patent), it can often be difficult to find that reference that discloses every one of the multiple claim elements.  Many patent claims, however, have one or more individual claim elements that would generally be considered routine or conventional. In that case, a prior art search can sometimes be facilitated by temporarily setting aside these routine elements and focusing the search instead on the inventive step or concept of a claimed invention that is the subject of the search.The term “inventive concept” is often loosely used, but one gets the impression when reading patent-related articles that the meaning of the term is generally understood and a non-issue. Merriam-Webster dictionary defines “concept” not just as an idea but an abstract idea. This understandably confounds many people who are told that mere ideas or abstract ideas are not patentable. For the purpose of this article, an “inventive concept” refers to the specific feature(s) or aspect(s) of the claimed invention that distinguishes it from prior art. An alternative definition that has been around for some time proposes that the inventive concept represents the inventor’s contribution to the field of the invention. Fortunately, for conducting prior art search, one need not delve into a legalistic or scholarly dissection of the meaning of the term “inventive concept,” unless your job requires you to do that.


    1. But how does one identify a claim’s inventive step or inventive concept, or something close to it, for prior art search purposes? There are various ways to do that, but one way is to just select those element or combination of elements of a claim that seem or are clearly novel (or at least non-routine) and thus presumably represent the inventive step or concept of the claimed invention. Another way is to find clues usually scattered throughout the patent specification, when it’s not clear which of the claim elements are novel or when statements expressly identifying the inventive concept in the specification can’t be found. For example, the background of the invention section of the patent at issue (i.e., the patent which is the focus of the search) will typically briefly describe some prior art and will sometimes also suggest or identify the inventive concept, which can be one or more components, steps, features, or functionalities of a device, system, or process that the patent states are missing in those cited prior art but are included as elements of the claimed invention.


  1. Look at the Patent File Wrapper or Prosecution History.

Sometimes, it’s difficult to deduce what a claimed invention’s inventive concept is because no single element can be clearly identified as such, it’s not clear which specific combination of claim elements constitute the inventive concept, and the specification itself also doesn’t provide a clue. In that case, reviewing the patent’s file wrapper or prosecution history can sometimes be helpful. For example, the inventor will sometimes suggest or explicitly state—in response to the examiner’s one or more rejections pertaining to the claimed invention in  an office action—which specific one or more claim elements the inventor considers to be the inventive step or concept. In some cases, one might also be able to deduce an inventive step or concept based on the one or more claim elements that the inventor amended or added into a previously rejected claim that was eventually allowed by the examiner based on the  claim amendment.


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1. Parola Analytics and Avontis are distinct entities and operate independently. Any references to Avontis or its services do not constitute a legal partnership. 

2. Parola Analytics does not provide legal services. Our services are limited to research and technical analysis. Any information provided by Parola Analytics should not be construed as legal advice.