Prior Art Search – An Overview

Prior art search has become a fundamental part of any business that deals with a significant number of innovative technologies and/or processes. For successful patent filing, an extensive prior art search is indispensable. For example, the European Patent Office (EPO) has recorded a steady growth in the number of patent filings from 2014 to 2018 with an average annual increase of 4.6%. This highlights the increasing importance of prior art searching as well as analysis in all modern industrial environments. Without exhaustive prior art searches and comprehensive prior art analysis, companies seeking to compete within a challenging market or technological domain can face litigation and infringement threats.

Different Types of Prior Art Searches

Prior art search is one of the initial steps before filing a patent. It involves searching for all existing prior arts that are nearest to the given technological innovation within the same domain. For example, in the US, several technological domains have unique innovations protected by intellectual property rights (IPR). Therefore, prior art searches help determine the novelty of an innovation worldwide, so that the patent is granted. Now, there are several different types of prior art searches that businesses can opt for based on their objective.

prior art search
Fig.1: Types of Prior Art Search
  • Novelty and Validity/Invalidity Searches: These involve both patent literature and non-patent literature search and analysis. While novelty searches are performed for the purpose of filing a patent application, validity/invalidity searches are performed to check or challenge the validity of a patent/application.
  • FTO Searches: These involve legally active patent literature searches and analyses them based on specific geographic regions. The searches are performed to determine the clearance of a technology/product in a market.
  • Infringement Searches: These comprise searching and analysing non-patent literature to identify patent infringements by third parties.
  • Landscape and State of Art Searches: These searches deal with both patent and non-patent literature searches (depending on the requirements) to understand the existing state of any given technology.
  • Chemical or Markush Structure Searches: These searches are focused on finding similarities between chemical structures of innovative chemical compounds whose IUPAC names have not been disclosed.

  • Biological Sequence Searches: These searches are performed to identify nucleic acid or protein sequences disclosed in a prior art document, in their standard sequence format.

Additionally, all these searches include thorough analysis which is used to guide strategic business decisions of companies regarding their intellectual property (IP).

Prior Art Search: Objective and Process

Fig.2: Why prior-art analysis is needed

Prior art searches vary in search and analysis scope according to the objective. There can be various objectives like filing a new patent to safeguard IP, enforcing patent rights, determining new areas of research or market clearance in a region. The search scope and analysis help in achieving these objectives involving a literature searching and analysis phase – performed in a solution-centric manner. The following steps elaborate on these phases.

Steps Involved in Prior Art Search and Analysis

Step 1: Identifying Key Concepts to Formulate Search Strategy

The first step in prior art search comprises formulating a strategy to conduct the search – it deals with identifying the key concepts, based on which, a plan can be prepared. In this step, different keywords, synonyms and variations of search keywords, citations, dates, jurisdictions, assignees, and technology classes are identified.

Following this, the search strategies can include searching for patent and/or non-patent literature, invention disclosures, or even products. For example, when searching for chemical or biological patents, the structure and sequence of searches should also be planned. These strategies are usually defined by the type of prior art needed, which is based on the objectives and requirements of the search.

Step 2: Formulating Search Queries

Search queries are created to capture the key essence of an innovation’s concept. These search queries are put through several free databases like Google Patents, USPTO, Espacenet, the Lens, etc. Similarly, paid databases like Derwent Innovation, Questel Orbit, etc., are also used. Various search fields in these databases are used in different combinations to capture results comprehensively, while reducing noise from irrelevant results. Apart from prominent keywords-based fields, assignee, classes and citations fields are also used while preparing search queries.

This step forms the basis for prior art analysis. The process itself is quite dynamic as there is a need for constant tweaking so that the most relevant information can be documented for further analysis. Therefore, one of the objectives of this step is to trim down the irrelevant results from the collected search results to enable accurate analysis in the subsequent step.

Step 3: Beginning the Prior Art Analysis

In prior art analysis, specific links need to be identified between the keywords that are used in prior art searches, so that a correlation can be found between the search results and the given innovation. After conducting the prior art analysis, the results are then screened meticulously. This is almost like pruning method where the usefulness and relevancy of the prior art being analysed is evaluated against the required objectives of the prior art analysis.

The context of the documents is analysed and is matched with the given innovation or invention according to the objectives. For instance, the steps can differ while conducting invalidity searches instead of patentability searches. A detailed analysis of the overlaps between the search-hits and the given innovation within a limited data set is performed manually. If general trends are found in a large data set within a larger technological domain, then this task can be automated. Generally, patent practitioners perform detailed analysis to identify specific overlap between search-hits and the invention of interest within a limited data set.

The step is conducted with clear objectives of generating a wholesome picture of the closeness of other existing results with the given invention. The step aims to explain links of the subject technology with existing patent and non-patent literature so that research and development teams can work on their inventions according to the insights developed.

Step 4: Presenting the Prior Art Analysis

Presentation of the analysis is subject to the requirements and the final objective. Prior art analysis is usually presented with required texts extracted from a document or a feature-wise mapping concerning the given innovation or invention. It can also be presented in a tabular form by checking and unchecking taxonomy categories for the given innovation or invention in the case of landscape or FTO searches. Claim mapping is one of the standard formats followed for invalidity and infringement searches. Finally, prior art analysis clearly presents whether the documents are closely linked to the subject invention. In case they are, prior art analysis explains the link.


Prior art search is a crucial part of IP Analytics that supports business intelligence. While performing prior art searches, developing insights from the most relevant literature is the crucial step in formulating a business strategy. Such insights are captured by intelligently researching literature through various databases and further analysing the closest literature to meet the end objectives.

Sagacious IP’s patent information searching services are designed to offer businesses pertinent prior arts in a timely and cost-effective manner. Our patent information search services include patentability search, invalidity searches and FTO searches.

-The Editorial Team

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