Who is the Person of Ordinary Skill in the Art, anyway?

Attached to every patent application is a Person of Ordinary Skill in the Art (POSITA). The POSITA is not real; it’s a hypothetical person having average, or ordinary, level of knowledge and skill in the field of the invention. They’re not a genius or an automaton, and they have an average level of creativity.

The POSITA plays a key role in at least two patent requirements:

• teaching the public how to make and use the invention, and

• non-obviousness of the invention compared to the prior art.

But who exactly needs to be taught? And who makes the inherently subjective decision that something is “obvious” relative to something else? The answer to both is the POSITA.

The POSITA is a flexible standard that varies with each invention. For a new drug compound, they might be a medicinal chemist familiar with a certain disease, while for an AI-related invention, they might be a computer scientist. The goal is efficiency: a computer scientist might need an exhaustive amount of teaching to do organic synthesis. At the same time, a chemist might look at two neural networks and have no idea whether the differences are obvious or not.

Another important feature of the POSITA is they have knowledge of the entire body of prior art. Prior art is the main tool Examiners use to establish the knowledge of the POSITA underyling every obviousness rejection.

Sometimes external evidence, such as from dictionaries or scientific databases, can be submitted by the applicant, to show what the POSITA would know and refute an Examiner’s assertion. This can be a quick and cost-effective alternative to conducting additional experiments and/or submitting expert declarations.

For example, the Examiner might misinterpret a particular term or unit of measurement, or argue it’s so unusual that the POSITA would not know what it means. These rejections can be hard to overcome by argument alone. If the specification doesn’t clear this up, the applicant can consider submitting external evidence, such as an Internet article explaining or using the term. This evidence can be used to show what the POSITA would know and clear up the discrepancy. At the very least, it could force the Examiner to produce references rather than relying on their own knowledge.

Care should always be taken when submitting external evidence, to ensure no part of the evidence can be realistically used as applicant-admitted prior art. If there’s any uncertainty, filing a declaration might be considered instead.