Choueifaty v Canada: The End of the Problem-Solution Approach for Software Patents?

By Liz Gray

On August 21, 2020, the Canadian Federal Court rejected the problem-solution approach adopted by the Canadian Intellectual Property Office (CIPO) for assessing patentable subject matter under the Patent Act.  The problem-solution approach has long been the standard used by CIPO to determine whether a claim element is “essential” to the invention for the purposes of claim construction.  As set out in Chapter 12 of the Manual of Patent Office Procedure (MOPOP), purposive construction requires the Commissioner to:

  • use a fair, balanced and informed approach;
  • identify the person skilled in the art;
  • identify the common general knowledge;
  • identify the problem and solution; and
  • determine which elements of the claim solve the identified problem.

That is, according to MOPOP, only elements of the claim that solve the identified problem are “essential elements”.  Under this approach, claim elements that do not solve the identified problem are not essential to the claim, regardless of whether they (a) have a material effect on the operation of a given embodiment; (b) are found in the prior art or are novel and non-obvious; and/or (c) transform non-patentable subject matter into subject matter that meets the definition of “invention” for the purpose of section 2 of the Patent Act.

This approach has long been considered questionable in light of case law, but had not been successfully challenged in court until recently.  In Choueifaty v Canada (2020 FC 837), Justice Zinn held that the problem-solution approach is incorrect and “akin to using the ‘substance of the invention’ approach discredited by the Supreme Court of Canada” (para. 37).  Rather, to determine whether a claim element is essential or inessential, the Commissioner must use the purposive construction approach set out by the Supreme Court in the seminal cases of Whirlpooland Free World Trust—and, in particular, the Commissioner must consider the inventor’s intention, something the problem-solution approach fails to do.

In his judgement, Justice Zinn reiterated the test from paragraph 55 of Free World Trust:

  1. Would it be obvious to a skilled reader that varying a particular element would not effect the way the invention works? If modifying or substituting the element changes the way the invention works, then that element is essential.
  2. Is it the intention of the inventor, considering the express language of the claim, or inferred from it, that the element was intended to be essential? If so, then it is an essential element.

Under this test, essential elements of a claim are not required to solve an identified problem.  Moreover, the inventor’s intention must be considered when construing the claims.  Although Choueifaty is likely to be appealed, its welcome clarifications may smooth the path to granting patents for computer implemented inventions (CIIs).

Please reach out to our experts with any further questions: Art Brion and Natalie Raffoul.

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