Patent Search Strategy Formulation: 6 Best Practices to Consider

Every company – big or small, intends to protect its inventions through IP rights such as patents. In order to obtain patents, companies must file applications with the concerned patent office. However, before that, they must determine whether their inventions are eligible for patent protection. The best way of ascertaining this is by conducting patent searches. To ensure that these searches are effective, it is imperative to first devise a robust patent search strategy.

The following article explains the six best practices that can help you formulate a robust strategy for performing high-quality patent searches.

Outlining Patent Search

A patent search is carried out before patent filing to identify the closest prior-art and determine if the subject matter/invention is worth patenting. This step enables companies to save costs associated with patent prosecution in case an invention is rejected. Since performing in-house patent searches is often time-consuming, companies either conduct these searches with limited resources or outsource them.

How to Devise a Robust Patent Search Strategy?

Patent Search Strategy

Fig.1: Best Practices for Devising an Effective Patent Search Strategy

Formulating an effective patent search strategy is crucial for conducting patent searches successfully. A comprehensive strategy ensures that all the relevant patent documents related to an invention are captured. While devising such a strategy may seem daunting, these six best practices can make the process a breeze:

  1. Smart Usage of Search Operators – The first best practice for formulating a robust search strategy is using truncation in keywords or synonyms. In simple terms, truncations or truncation operators are symbols that substitute one or more characters, thereby letting you search for different variations of a term. Although searchers do know how to use these operators in different databases, they must learn to use them more efficiently.

Given below is the list of most common truncation operators used in two popular databases – Thomson Innovation and Questel Orbit.

Thomson InnovationAsterisk (*) – Searches any number of characters.ADJn – Searches terms adjacent to each other within n words, in the specified order.NEARn – Searches terms adjacent to each other within n words, in any order.Hash (#)–Thisreplaces exactly one character.
Questel OrbitAddition (+) – Searches any number of characters. Underscore Sign (_)– It allows simultaneous searching of terms that may be written as one or two words. It also retrieves results where there is a hyphen between terms. Interrogation sign (?) – Searches for 0 or 1 character. nW–Searches for words appearing within n words of one another in the written order. If n is omitted, the number defaults to one. nD–Searches for words appearing within n words of one another but in either order. If n is omitted, the number defaults to one. S– Searches for terms occurring in the same sentence. P–Searches for words in the same paragraph. Hash Sign (#)–Thisreplaces exactly one character.
Table 1: Common Truncation Operators Used in Thomson Innovation and Questel Orbit

Let us discuss an example to know the kind of false hits that can be captured using truncation operators in our search term sets.

Suppose we put the interrogation sign (?) after the word “Car” and execute a search. The intended outcome for this search is either “Car” or “Cars”. However, the usage of this truncation operator also captures the word “Card”, which is a false positive. To avoid capturing such unwanted results, we need to select our operators carefully.

2. Running Targeted Keyword-Based Search Query – The next best practice for devising an effective search strategy is running a targeted keyword-based search query. This is crucial to address the issues related to the wrong classifications done by National Patent Offices.

To help you understand this best practice better, we have analyzed and discussed an Indian patent below. The invention mentioned in this patent is related to the domain of an outer rear-view mirror assembly in automobiles. The Indian Patent Office had tagged this invention under the wrong class related to physics, i.e., G01T (measurement of nuclear or x-ray radiation). However, the correct tagging is B60R 1/06, which relates to the rear-view mirror arrangement mounted on a vehicle exterior.

Patent Search Strategy

Fig.2: A fold-unfold mechanism for outer rear-view mirror assembly

As the Patent Office had tagged the invention incorrectly, we could have missed this result if we had restricted all our search strategies to the relevant classifications only. This means that in order to avoid such misses, we must run at least one of the search strategies without the restriction of any classification.

3. Replicating Search Strings Using Native Language Keywords – Yet another best practice for effective search strategy formulation is the replication of search strings using native language keywords. Adopting this best practice increases the chances of capturing non-English search results that might have been missed due to machine translation errors. For instance, if most of the prior-arts for an invention are published in Chinese, Japanese, or other non-English languages, then it is advisable to use both English and native language keywords while performing searches to avoid missing out on relevant results.

4. Creating Assignee Corporate Tree for English and Native Searches – The next best practice for ensuring an effective search strategy is to create an assignee search string in English as well as the native language of the respective assignees. For instance, sometimes, the search involves scouting the details corresponding to the assignees related to non-English countries. In such cases, the searches should be run by a native language expert and parallel searches should be performed on native language databases. Since the coverage of native language databases is more than English patent databases, the chances of missing out on the relevant prior arts are reduced drastically. Furthermore, if there is no budget constraint, native language experts should analyze the results in the native language only to further eliminate misinterpretation of prior arts due to machine translation errors.

5. Searching for Broader Classifications – Another best practice for devising an effective search strategy is to cover broader classifications while running a search string. The reason is that patents are sometimes tagged under broad classes rather than the relevant narrow classes. Therefore, if only narrow class searches are performed, we might miss out on patents tagged under broader classes.

For instance, an Indian patent for an invention whose subject matter was related to an arrangement of button-operated outward swivelling motion of the conventional rear-view mirror had been tagged under B60R 1/00. However, it should have been tagged under B60R 1/072 as it was closer to the invention’s subject matter. Since the Indian Patent Office had tagged the invention under a broader class, we could have missed this result if the searches were restricted to a narrow class. This means that we must run at least one of the searches with broad classifications such as B60R1 or B60R to avoid such misses.

6. Covering Different Application Areas – The last best practice for ensuring a robust patent search strategy is related to the application area of an invention. To help you understand this better, let us discuss an example:

Suppose we need to search for a “check valve” in a braking module. In this case, we first run patent searches for the braking module in the automotive domain. Thereafter, we perform some general searches, i.e., searches beyond the automotive domain. Chances are that while searching in other domains, we might find a patent document with a similar check valve. This means that if we are unable to identify a similar invention in the application area/domain of the invention, we should broaden the search scope and include all other application areas to avoid missing out on relevant patents.


Companies seeking patent protection for their inventions spend a significant amount of time and money in performing patent searches. This is because these searches determine the fate of inventions, i.e., their patent-worthiness. Given the crucial role these searches play in gauging patentability, it is imperative to perform them comprehensively. The best way of doing this is by formulating robust patent search strategies.

If you are pressed for time or are running on a tight budget, seeking expert guidance is paramount. Our Patentability Search service aims to provide clients the right prior art at the right time. These searches help in validating the novelty of inventions, retrieving the patentable subject matter, and making decisions related to patent filing. To know more about this service, click here.

-Shubham Tyagi (Engineering) and the Editorial Team

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