Key Takeaways

  • PHOSITA (“person having ordinary skill in the art”) is a critical legal standard in patent law used to assess obviousness, enablement, and claim interpretation.
  • Courts and the USPTO rely on PHOSITA to define the knowledge and perspective of a hypothetical skilled person at the time of invention.
  • The scope of a PHOSITA’s expertise is shaped by the field of invention, prior art, and the problem the patent seeks to solve.
  • Defining PHOSITA too broadly or too narrowly can significantly impact patent validity and litigation outcomes.
  • Emerging technologies like AI are reshaping what constitutes “ordinary skill,” raising new questions for how PHOSITA should be defined in the future.
  • Legal debate continues over whether PHOSITA should be defined based on the patent specification or the claims, with important implications for obviousness and enablement determinations.

PHOSITA stands for “person having ordinary skill in the art.” PHOSITA is used regularly in a court of law when developing a patent. It helps determine the viability of an invention based on the skills and expertise of those having very specialized training in very narrow areas.

How Specialized is a PHOSITA?

PHOSITA is a type of hypothetical person that has omniscient understanding of a publication in the same field on the day of the filing, but ordinary skill. To be patentable, the invention cannot be obvious with regard to PHOSITA.

For instance, if you want to patent a widget that is a connection between a “doohickey” and a “thingy” in an engine, it may be obvious to an engine designer, interesting to a marine engine designer, and completely oblivious to the layperson who never deals with engines.

When obtaining an examination with the USPTO, the level of PHOSITA is typically not covered as well as it could be. PHOSITA can be an issue of debate in court. In general, the PHOSITA needs to be specific to the field.

Determining PHOSITA’s Knowledge and Perspective

Understanding what qualifies as “ordinary skill” is central to applying the PHOSITA standard. Courts typically assess several factors to define the PHOSITA for a particular invention, including:

  • Educational background and training common in the field.
  • Practical experience and familiarity with existing technologies.
  • Awareness of prior art and the general state of the field at the time of invention.
  • Problem-solving approach that a skilled artisan would reasonably adopt.

This perspective is not omniscient but assumes that a PHOSITA is aware of all publicly available prior art and has the ability to apply common sense and routine experimentation. For instance, in Graham v. John Deere Co., the Supreme Court emphasized the PHOSITA’s vantage point as critical to assessing whether a claimed invention would have been obvious to someone with ordinary expertise.

However, defining that expertise too broadly can make many inventions seem obvious, while defining it too narrowly can improperly grant patents for incremental improvements. Courts often strike a balance by focusing on what problems a PHOSITA would be motivated to solve and what solutions they would reasonably consider at the time of invention.

PHOSITA Case Reissued as Precedential

PHOSITA stands for “person having ordinary skill in the art.” A lot of the patent laws will depend on this hypothetical person. In particular, the obviousness and the construction determination will depend on how the court defines PHOSITA in the suit. Still, there is little guidance when it comes to Federal Circuit case law.

The CAFC has now reissued an opinion that is identical as precedential, meaning it is worth thinking about any implications and what they could be.

There was a case recently involving ofloxacin, which is an antibiotic that is used topically for treating infections in the ear. While there are many ramifications to applying topical solution to the ear, those specializing in the field are equipped to know that ciprofloxacin did not show any damage.

While ofloxacin and ciprofloxacin are similar antibiotics with a similar structure, those who were cognizant of the success of ciprofloxacin would have had the necessary motivation to utilize ofloxacin in the same way.

However, the District Court had general physicians and pediatricians within the group of those who have ordinary skill in this particular art.

Since they were non-specialized, they did not use or rarely used ciprofloxacin to help aid infections of the ear. The court then ruled that the success of ofloxacin wouldn’t be obvious to PHOSITA.

The Federal Circuit eventually reversed the decision, stating that the District Court did not limit the PHOSITA to specialists, such as otologists and those working to develop formulations of pharmaceuticals.

Because the smaller subsection of people with this particular expertise would know that ciprofloxacin would be successful, using ofloxacin would be obvious. In this case, the CAFC came to the best result. PHOSITA’s art field relies on the nature of the invention. Those who do not specialize in this field would not be included in the class of skilled artisans.

This case firmly illustrates the possible risks of setting the level of ordinary skill much too low. If you include general physicians in a class of skilled artisans in cases such as this, there would be little to no invention of pharmaceuticals, as they would not be obvious.

Specification vs. Claims: Where Should PHOSITA Be Defined?

One of the most debated issues in patent law is whether a PHOSITA should be defined based on the specification or the claims of a patent. This distinction matters because it shapes how courts interpret obviousness and enablement.

  • Specification-based approach: Some courts and the PTAB have reasoned that PHOSITA should be defined in light of the invention disclosed in the specification. This view often narrows the scope of the skilled artisan’s perspective, potentially making it easier to prove enablement but harder to prove obviousness.
  • Claims-based approach: Others argue that PHOSITA should be defined relative to the scope of the claims, as they represent the legal boundaries of the invention. This broader view aligns PHOSITA’s expertise with the claimed invention’s breadth and ensures that enablement and obviousness are evaluated on the same footing.

The Federal Circuit has not settled this debate, but the trend in recent PTAB decisions, such as Axonics Modulation Technologies v. Medtronic, leans toward a claims-focused definition. This approach better aligns the PHOSITA analysis with the statutory requirements of §103 (obviousness) and §112 (enablement).

Time to Reconsider PHOSITA

Crucial to issuing patents is ensuring that there is consistency and stability during the examination process.

What do patents generally mean?

  • You need to think about what the patent focuses on with regard to being obvious and how it relates to the merit of the invention.
  • The patent document must explain fully what the invention is and the rights that have been granted to the person filing the application.
  • Clarity of a patent does not always have a one-size approach.
  • It is a technical document that explains a new invention and is not understandable by a layperson.
  • What helps one understand a patent is dependent on that person who is reading it and who its directed to. This is where PHOSITA comes into play.

AI and the Future of PHOSITA

The rise of artificial intelligence is forcing courts and policymakers to rethink the PHOSITA standard. Traditionally, PHOSITA is a human construct—a proxy for what a skilled person could know or do at a given time. But as AI becomes a routine tool in research and development, the baseline for “ordinary skill” is shifting.

AI can rapidly synthesize prior art, propose new chemical structures, and even design mechanical systems, potentially elevating the capabilities of a typical skilled artisan. This raises key legal questions:

  • Should the capabilities of AI-assisted inventors redefine what is “obvious”?
  • If AI tools are widely accessible, should a PHOSITA be assumed to use them?
  • Could this raise the bar for patentability, making it harder to secure patents for incremental innovations?

Some scholars argue that ignoring AI would make the PHOSITA standard outdated and overly permissive. Others caution that incorporating AI too aggressively could chill innovation by raising the bar unrealistically high. As courts confront these questions, the definition of PHOSITA may evolve to include not just human expertise but also tools commonly used by those in the art.

Frequently Asked Questions

  1. What does PHOSITA stand for in patent law?
    PHOSITA stands for “person having ordinary skill in the art.” It is a legal standard used to assess whether an invention is obvious, properly enabled, or sufficiently described from the perspective of a skilled artisan.
  2. How is a PHOSITA defined in practice?
    Courts consider education, work experience, familiarity with prior art, and problem-solving abilities in the field to define PHOSITA. The definition is specific to the technology and context of the invention.
  3. Why is the PHOSITA standard important?
    It ensures that patents are granted only for truly innovative ideas and not for inventions that would have been obvious to someone with ordinary skill in the field at the time.
  4. Should PHOSITA be defined based on the patent specification or claims?
    This is a debated issue. Many experts favor a claims-based approach because it aligns the PHOSITA’s expertise with the legal scope of the invention.
  5. How might AI change the PHOSITA standard?
    AI tools can expand the capabilities of skilled artisans, potentially raising the bar for what is considered obvious or routine, which could significantly impact future patentability determinations.

If you need help with understanding PHOSITA and all that it entails, you can post your legal need on UpCounsel’s marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law, and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb.