Is it Patentable?


Is it patentable?  This is the ultimate question when considering how to protect your good idea.  The answer depends upon several considerations.  First, is it patentable subject matter?  Also is your idea already known?  If not already known, is it merely an obvious variation or combination of things that are known?

The most common barrier to patentability is that your invention or idea would be obvious to a person familiar with the technology relevant to the subject matter.  However everything is obvious with hindsight.  So how do you determine – “is it patentable?”


There are various categories or fact patterns that, if established, make an invention obvious.  Note the qualification that the facts must be established in order to reject your invention as merely obvious in view of known facts.  This is the burden that must be met by a patent examiner.

Factors of obviousness are:

  • (A) Combining prior art elements according to known methods to yield predictable results;
  • (B) Simple substitution of one known element for another to obtain predictable results;
  • (C) Use of known technique to improve similar devices (methods, or products) in the same way;
  • (D) Applying a known technique to a known device (method, or product) ready for improvement to yield predictable results;
  • (E) “Obvious to try” – choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success;
  • (F) Known work in one field of endeavor may prompt variations of it for use in either the same field or a different one based on design incentives or other market forces if the variations are predictable to one of ordinary skill in the art;
  • (G) Some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claimed invention.


Note that the above factors (established by the US Patent Office) all require an element of “predictability” or “reasonable expectation of success”.  Alternatively, there must have existed some “teaching, suggestion or motivation” in the prior art that would have hinted that the new combination would be achieve success.  (This is a variation of predictability.)

The question – Is it patentable? thus morphs into – Is it obvious?

There is no bright line test.  Every case is fact dependent.  However the patent examiner has the burden to establish and articulate an explicit written and fact based reason for justifying rejection of your invention as obvious.  You will then have an opportunity to challenge the examiner’s assertion.

In describing your invention, try to focus on the unexpected (not predictable) results or benefits.  Especially valuable would be references to prior art or known technology that would suggest your invention wouldn’t achieve the result or performance.

Remember that known technology must be in the same technical field as your invention or be directed to the same problem that your invention is solving to justify a claim of “mere obviousness”.   Non-analogous art cannot be the justification for rejecting your invention as “obvious”.


It is not possible to fully discuss the topic in this forum.  However this post does explore the issue and points out important questions to ask.  It also suggests things that should be emphasized in the specification (written description) of your patent application.

I am always available to discuss your specific circumstances or issues.  You can reach me a


©David McEwing June 2021