Patent Law News + Insights

How to Do a Prior Art Search Yourself

December 21, 2017

It’s very common for patent attorneys to discourage inventors from doing a prior art search on their own. As the argument goes, it’s best to leave the legal footwork to the legal experts.

But if you’re an expert in your field of science and engineering, outsourcing your prior art search may not always be the best use of your limited budget. You’re probably already well-equipped to conduct an effective prior art search on your own — with a little guidance from the professionals.

Can we really do an effective prior art search ourselves?

Back in the good old days, expert prior art searchers had access to more resources (specifically at the USPTO) than the ordinary person, and they used special techniques for effectively searching special patent databases.

But today, the internet provides 90 percent of the same value — for free.

And anecdotally, every time I’ve been to the USPTO, the search rooms have been virtually (or literally) empty, suggesting that people just don’t use them much anymore.

So yes, you can do the prior art search effectively on your own because the best search tools are available for free online.

When you still need a lawyer

You’re probably qualified to do your own prior art search if you’re an expert-level innovator who’s generally familiar with the existing work in your field.

But that doesn’t mean you should go through the entire patent process on your own! While you can conduct the prior art search yourself, you’ll likely still need a patent attorney to help you develop a patent strategy and analyze patentability.

On the other hand, if you’re working in a technical field where you don’t have extensive experience, you should probably hire someone to do the search for you.

Benefits of conducting a prior art search

By familiarizing yourself with the existing prior art, you enjoy the following six benefits:

  1. Avoid submitting patent applications with claims that are not patentable and will be easily rejected
  2. Determine whether your invention is novel compared to public prior art
  3. Develop a strong patent claim strategy before you file your patent application (and reduce the chance of extensive amendments)
  4. Account for close prior art when drafting your patent application. For example, you might want to describe advantages or improvements over relevant prior art, as this can help persuade the patent office that your invention is “non-obvious”
  5. Understand how your idea fits into the technological field
  6. Be better prepared to discuss your invention with a patent attorney and explain what aspects of your work might be patentable


How to conduct an effective prior art search

Simply put, a prior art search involves checking different databases to find out whether someone else has already described an idea similar to yours.

Here are five steps to follow to ensure your prior art search is comprehensive.

1. Brainstorm keywords to describe the invention

To conduct a thorough search, you’ll need to account for all possible keyword combinations that could exist in the prior art.

There are various reasons why other patents and applications may use unusual keywords:

  • The industry’s commonly accepted terminologies may have changed over time
  • Different industries may use different keywords to describe similar concepts
  • Many patent filings are translated from other languages to English

2. Search the patent databases

We recommend using the following patent search tools to kickstart your search:

Many practitioners find that the “classification” system used by the USPTO (that is, the classes and subclasses assigned to each patent) is not particularly useful for prior art searching. As such, we don’t recommend using it as the primary means to guide your search.

Instead, we recommend making a list of the top 10 patent documents for each keyword — and then looking at all the other patent documents that reference, or are referenced by, that patent document. This is sometimes called a “forward and backward” cross-reference search.

To do a “forward and backward” cross-reference search in Google Patents:

  • Open the page for the relevant patent that you’ve found.
  • Scroll to the bottom.
  • Refer to the sections for “Patent Citations” and “Referenced By.”
  • Scan the list to see if any of the titles look relevant, or click the links to review them in detail.

To do a similar search on the USPTO search interface:

  • View the relevant patent document.
  • Scroll down to “References Cited” to look backward at the documents cited in the patent you’ve found.
  • Click on “Referenced By” to look forward at patents that cite the patent you’ve found.

You’ll also see a section for “Non-Patent Citations.” While these documents are not always easy to find online, you may be able request a copy from the patent office.

3. Expand your search beyond patent databases

Prior art isn’t limited to only existing patents or patent applications; it includes all ideas that are publicly available and publicly disclosed. As such, a complete prior art search should extend beyond patent searching.

The following list is not exhaustive, but your prior art search could include:

  • A Google Scholar search for scholarly publications
  • Non-patent literature like articles, publications, or journals (printed or electronic)
  • Amazon or other commercial sites
  • The product pages of companies that might be innovating in the same space

4. Save all relevant results and documents

When filing your patent application, you want to cite the most relevant prior art to the USPTO. If the patent examiner has all the most relevant references at their disposal, you’ll end up with a stronger patent.

Additionally, this will ensure you satisfy your ethical duties of disclosure, candor and good faith to report prior art that could affect the patentability of a claim.

So make sure you save a list of all relevant results, as well as complete copies of the documents themselves. (We love a good spreadsheet!)

5. Know when to stop searching

Your goal is not to examine all the prior art out there. Rather, it’s to examine enough prior art to gain a comprehensive understanding of where your invention stands in the industry.

Because of the following reasons, it’s literally impossible to know the entire universe of prior art that may be relevant before you file a patent application.

For one, thanks to the 18-month publication window, some patent applications that qualify as prior art may not become public until later on.

For another, there may be relevant prior art that doesn’t show up in a typical search (even after they’re public). Examples include documents that are not indexed on Google, academic theses, and foreign language documents.

So if your search isn’t turning up much prior art, you might be tempted to keep going — but use your experience and common sense to decide when to call it a day.

What happens if I find prior art against my invention?

Finding prior art against your invention can be discouraging — but it may not necessarily invalidate your entire patent. In our FREE eBook, "Prior Art and the Patent Process," we discuss how prior art affects different types of patent claims, and what you can do to overcome prior art obstacles. Download it now!

prior art and the patent process

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Michael Henry

Michael Henry is a principal and the founding member of Henry Patent Law Firm PLLC. Michael specializes in creating comprehensive, growth-oriented IP strategies for early-stage companies who are developing emerging technologies.

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