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Patentable Subject Matter: Distinction Without a Difference?

Authored byGiselle Chin

Following the Federal Court's overturning of CIPO's oft-maligned "problem-solution approach" to determining patentable subject matter, CIPO has issued a new Practice Notice in response to the recent case law, Yves Choueifaty v Attorney General of Canada, 2020 FC 837 (Choueifaty).

By way of brief summary, the Practice Notice states that subject matter of impugned claims are first to be determined through purposive construction, as required by the Supreme Court of Canada, to determine whether each claim element is essential or inessential. Once the subject matter is identified, then it is determined whether that subject matter is patentable subject matter (per s. 2) and not a mere scientific principle or abstract theorem (per s. 27(8)).

However, although the Practice Notice appears to abolish analysis based on the "substance of the invention", it then creates and relies on a suspiciously similar concept of identifying the “actual invention” of the claim. It appears that whether the claim encompasses patentable subject matter will depend on what this "actual invention" is, rather than the Supreme Court mandated purposively construed essential elements.

It is not entirely clear how CIPO will determine what the "actual invention" of a claim will be. For instance, one of the computer-implemented Examples provided by CIPO states:

A computer-implemented method of analysing data from seismic measurements comprising:

a. Receiving the data from the seismic measurements;
b. Processing the data on a computer using algorithm X; and
c. Displaying the results of the analysis of step b.

In their analysis, CIPO concluded that although all of the above elements are essential, as purposively construed, only step b. forms part of the "actual invention". Steps a. and c. only represent generic input/output steps. Since step b. only encompasses an algorithm, which has no physical existence, the "actual invention" is prohibited under subsection 27(8) of the Patent Act.

However, a medical diagnostic method example provides:

A method of diagnosing whether a human subject is at risk for developing cancer, comprising:

a. receiving a report summarizing the level of X in a sample from the subject; and
b. comparing said level to the level of a non-cancerous reference sample, wherein an increase in the level of X relative to said reference indicates the subject is at risk for cancer.

Here, CIPO concluded that all of the above elements are essential, as purposively construed, and that in order to arrive at the diagnosis, the receiving element, comparing element and correlation element cooperate together to form a single "actual invention". However, since none of the elements in the “actual invention” provide any physicality, the subject-matter of the claim is not patentable subject-matter.

Thus, the "problem-solution approach" could be merely operating under the pseudonym of an "actual invention" approach. While there is little guidance as to how CIPO will consider claim elements to cooperate together to form a single "actual invention", there are a number of other useful points that can be gleaned from the Practice Notice.

  • If you are interested in filing for an invention that involves an algorithm or diagnostic method, the patent claims should incorporate the practical aspect of the algorithm's or diagnostic method's input and/or output. The Practice Notice suggests that physicality in the input or output of the method may help to render the subject matter patentable, subject matter-wise.
  • If you have abandoned an application in the last year due to subject matter eligibility, reinstating with claim amendments to include practical input or output steps may increase your chances of allowance.

Though CIPO’s approach to patentable subject matter does not seem to have drastically changed in view of Choueifaty, perhaps it is a start of a solution to the "problem-solution approach" problem.  

The Practice Notice is available here: 


Discussion of Choueifaty v Canada, 2020 FC 837 can be found here: