You can’t do that! Federal Court quashes the “problem-solution” basis for rejecting claims

August 31, 2020

In a recent decision, the Federal Court of Canada declared that the policy adopted by the Canadian Intellectual Property Office (“CIPO”) for determining subject matter eligibility of claims to computer-implemented inventions is improper.  The CIPO’s policy served as a basis for rejecting many patent applications in Canada, so the decision is welcome news to applicants.  Absent a successful appeal of the decision, this recent development in the Canadian patent landscape will remove a significant roadblock to obtaining protection for computer-based inventions in Canada.  This decision is also expected to remove a hurdle in the patenting of inventions relating to medical diagnostic methods, many of which suffered the same fate as computer-based inventions.


In 2013, the CIPO issued Practice Notice PN 2013-02, entitled Examination Practice Respecting Purposive Construction to guide examiners in the examination of patent applications.  In construing a claim under PN-2013-02, the examiner is required to first analyze the application to identify the “problem” being addressed and the proposed “solution” to the problem presented by the invention.  In the course of this so-called problem-solution analysis, the examiner must then identify those elements or features that are essential for providing the construed “inventive solution” and to distinguish them from non-essential elements. 

In 2013, the CIPO also issued Practice Notice PN 2013-03, entitled Examination Practice Respecting Computer-Implemented Inventions, which provided more detailed guidance to examiners for the examination of computer-implemented inventions.  In particular, PN 2013-03 stipulates that, following the “problem-solution” analysis, a computer may be found to be a non-essential element of the invention, even if it is recited in a claim.  In such case, the claim, stripped of its “technical” features may be construed as only encompassing an abstract concept or a series of mental steps and therefore rejected as not constituting patentable subject matter.

The CIPO issued a further Practice Notice in 2015, PN 2015-02, entitled Examination Practice Respecting Medical Diagnostic Methods.  This Notice also reiterated the problem-solution approach to claim analysis and directed that, for an application relating to a medical diagnostic method, an examiner must first determine whether the application aims to solve a “data acquisition problem” or a “data analysis problem”.  Where a data analysis problem is identified, the invention is typically deemed to comprise a disembodied idea, i.e. a series of mental steps, resulting in the claim being rejected as constituting non-patentable subject matter.

Based on the guidance provided by the above-mentioned Practice Notices, many patent applications, particularly those directed to computer-implemented inventions, have been refused and finally rejected.  Unfortunately, such applications also did not fare well under appeal.  Between January 2016 and August 2020, 70 patent applications were referred to the Patent Appeal Board for reconsideration after being rejected under the problem-solution analysis.  In all 70 cases, the claims were refused. 

The decision

In Yves Choueifaty v. Attorney General of Canada, Choueifaty appealed the Patent Appeal Board’s final refusal of his patent application to the Federal Court of Canada.  The claims of the application had been refused by the CIPO for being directed to non-patentable subject matter, where such rejection was predicated upon the “problem-solution” analysis as summarized above. 

The Court allowed the appeal and, in no uncertain terms, held that the claim construction process outlined in the CIPO’s Practice Notices was improper and that “using the problem-solution approach to claims construction is akin to using [an] approach discredited by the Supreme Court of Canada.” 

The Court emphasized that the correct approach for construing claims is to apply a “purposive construction” as stipulated by the Supreme Court (Free World Trust v Électro Santé Inc.).  In particular, the Court in Choueifaty stipulated that a claim must be construed on the basis of the inventor’s purpose or intent and the essentiality of a claim element is to be determined by asking the following questions:

  1. Would it be obvious to a skilled reader that varying a particular element would not affect 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.

Thus, the Court held that in a proper claim construction a claim element can only be said to be non-essential where it is shown both that on a purposive construction of the words of the claim it was clearly not intended to be essential and that at the date of publication of the patent the skilled addressee would have appreciated that a particular element could be substituted without affecting the working of the invention.  The Court also found that the CIPO’s problem-solution approach focused only on the second aspect and ignored the inventor’s intent. 

The Court allowed Choueifaty’s appeal and remanded the application to the CIPO with instructions to conduct a fresh examination under the proper claim construction. 


Subject to the decision being successfully appealed, the CIPO’s practice of conducting a problem-solution analysis for determining essentiality of claim terms has been put to rest.  Under the correct process, as held by the Court, the recitation of elements in a claim cannot be simply discounted based on a purported “solution” that is derived from reading the application.  Although the claims of an application must still meet other statutory requirements for patentability, the Choueifaty decision disposes of a major hurdle that many applicants have been facing, namely, having their claims refused before the other criteria are assessed. 

As noted above, the CIPO’s problem-solution guidance formed the basis for analyzing both computer-implemented inventions and medical diagnostic inventions.  Thus, although the Choueifaty decision relates to an application directed to a computer-implemented invention, it is believed that the court’s holding that the threshold problem-solution analysis is improper will also be helpful in securing protection for inventions relating to valuable medical diagnostic methods. 


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