It has now been almost six months since the Canadian Intellectual Property Office (CIPO) released practice notices PN 2013-02 and PN 2013-03, the former concerning purposive claim construction and the latter concerning examination practices for computer-implemented inventions, collectively referred to in this article as the “Guidelines.” (Click here for our initial news release). Overall, the new Guidelines are a positive development for patent applicants in Canada.

This article provides a brief summary of the old examination approaches that have been abolished, the new approaches that replace them, and some practice tips for increasing the likelihood of success under the new Guidelines.

The New Guidelines

What’s Gone

The new Guidelines abolish all of the examination approaches that CIPO adopted in 2009, which were subsequently struck down by the Courts in the Amazon decisions (, Inc v Commissioner of Patents2010 FC 1011, affd. in part 2011 FCA 328). The abolished approaches included:

Form and Substance, Inventive Concept and Contribution Approaches: The Guidelines recognize that it is not permissible to assess statutory subject-matter based on the “substance” of the invention, the “inventive concept” or the inventive “contribution.” Instead, any assessment of patentability must be based upon a proper purposive construction of the claim, in accordance with the principles set forth by the Supreme Court of Canada.

Non-Technological Exclusion: The Guidelines also effectively concede that there is no exclusion from patentability of “non-technological” subject-matter, and there are no categorical exclusions of business methods or other allegedly non-technological areas from patentability.

Physical Agents and Objects Test for Method Claims: The Guidelines omit the narrow physicality test from a 1970 lower court decision which CIPO had previously applied, whereby a method claim would qualify as statutory subject-matter only if it involved physical agents acting upon physical objects to produce a change in the character or condition of those objects. That test has been supplanted by a broader test based on subsequent decisions of the Supreme Court of Canada and the Federal Court of Appeal.

These changes are a significant and welcome development for applicants.

What’s New

The Guidelines acknowledge the need for CIPO to base any assessment of patentability upon each claim as purposively construed in accordance with the principles set forth by the Supreme Court.

Generally, purposive construction as set forth by the Supreme Court involves identifying each element of the claim as essential or inessential. It appears from the Amazon decisions that CIPO may not have to consider non-essential elements when assessing patentability.

Purposive construction, according to the Supreme Court in Free World Trust v Électro Santé Inc2000 SCC 66, generally entails a presumption of essentiality and the application of two principles:

“For an element to be considered non-essential and thus substitutable, it must be shown either (i) that on a purposive construction of the words of the claim it was clearly not intended to be essential, or (ii) that at the date of publication of the patent, the skilled addressees would have appreciated that a particular element could be substituted without affecting the working of the invention, i.e., … both the element specified in the claim and the variant … ‘… would obviously work in the same way’, … meaning that the variant (or component) would perform substantially the same function in substantially the same way to obtain substantially the same result.”

For convenience of terminology, principle (i) is referred to in this article as the “Claim Language Primacy Principle,” while principle (ii) is referred to as the “Material Effects Principle.”

If the above quotation of the two principles from Free World Trust were to be read in isolation, the terms “either” and “or” might be interpreted as suggesting that essentiality can be determined by considering either one of the two principles, without necessarily considering the other. However, other passages ofFree World Trust clarify that the Claim Language Primacy Principle applies universally, and acts as a limit upon the Material Effects Principle. For example, the Court ruled that non-essentiality must not be presumed from a mere finding that variants of the element would not have any material effect on the way the invention works. Instead, the Court described the Claim Language Primacy Principle as being applicable to determine essentiality of an element “irrespective of its practical effect,” “even though it could have no material effect upon the way the invention worked.” It is therefore clear from Free World Trust that even if the Material Effects Principle fails to indicate essentiality, the Claim Language Primacy Principle must still be considered and applied before the presumption of essentiality can be rebutted.

However, the Guidelines do not discuss or consider the presumption of essentiality or the Claim Language Primacy Principle at all. Instead, the Guidelines focus only on the Material Effects Principle. The effect of this omission is that it is easier to show that a particular element is non-essential under the Guidelines than if both Principles were considered.

Some aspects of the Guidelines may pose new challenges for applicants, notably:

  • The Guidelines adopt a problem-and-solution approach to identifying the essential elements, which may conflict with the results flowing from the Supreme Court’s approach.
  • The Guidelines distinguish between “computer problems,” meaning a problem with the operation of a computer, and “non-computer problems,” meaning a problem whose solution can be implemented using a computer.
  • The Guidelines suggest that if the claim solves a non-computer problem, the Examiner will be more likely to conclude that the computer is “superfluous” or non-essential (which in turn will likely lead to a non-statutory subject-matter rejection). The Guidelines assert that a scant level of implementational detail in describing the computer or its operation may favour a finding that the computer is non-essential.

Other aspects of the Guidelines are helpful, such as:

  • The recognition that if a computer is an essential element of the claim, the claim will generally constitute statutory subject-matter. The pragmatic significance of this recognition cannot be overstated. Previously, applicants sometimes needed to engage in lengthy discussions of the principles of statutory subject-matter. Now, however, the whole issue of statutory subject-matter may boil down to a question of claim construction and whether the computer is an essential element.
  • With respect to the test for method claims to qualify as statutory subject-matter under the category of “art,” the outdated “physical agents and objects” test has been replaced with a more lenient physicality requirement based on the Amazon decisions, which requires either “something with physical existence, or something that manifests a discernible effect or change.”

How the New Guidelines are Being Applied in Practice

Although it is still too early to tell how CIPO’s application of the Guidelines will evolve over time, the first few months have revealed mixed results.

On the one hand, a number of applications which had previously been rejected for non-statutory subject-matter have either been allowed or have received Office Actions in which the non-statutory subject-matter objections were withdrawn. This suggests that the number of applications subjected to non-statutory subject-matter objections under the new Guidelines may be fewer than under the examination approaches of 2009-2012.

On the other hand, a number of Office Actions have issued in which non-statutory subject-matter objections have been based on assertions that only a few elements of a claim are essential and the remaining elements are non-essential.

Practice Suggestions Under the New Guidelines

The strategy that is appropriate will depend of the stage of prosecution.

At the drafting stage, as much detail as reasonably possible should be included describing the computer and its use. Ideally, the specification and drawings should include a combination of flow charts showing the major routines or algorithms, and block diagrams showing the processor and the defined memory registers or buffers that are used in the routines. These details will reduce the likelihood that CIPO may infer non-essentiality of the computer from a lack of implementation details in the specification. If the method actually does solve a problem with the operation of the computer, this should be emphasized in the specification, since this will favour a finding of essentiality of the computer under the Guidelines.

At the first Office Action, when faced with findings of non-essentiality and non-statutory subject-matter, an appropriate response would be to amend the claims to recite more structural elements such as a processor, a display, an input device, etc. If the use of any such physical element is found to be an essential element, the claim should satisfy the judicial requirement that there be either “physical existence, or … a discernible effect or change.” As noted above, the Guidelines confirm that if a computer is an essential element, the claim will generally be statutory. The same reasoning would appear to apply to essentiality of any other structural element.

When amending the claims to recite a processor or other structure, applicants should also consider whether to repeat some of the preamble in the body of the claim, in limitations relating to the processor or other structure. This may facilitate arguments that the processor or other structure is essential to carry out the purpose stated in the preamble.

Applicants should also review their independent claims to ensure that the claim does in fact require a “discernible effect or change.” Where appropriate, output steps such as displaying or otherwise presenting the results to a user should be recited for this purpose.

These amendment strategies may be coupled with appropriate arguments concerning purposive claim construction and the essentiality of elements. Where appropriate, arguments based on other parts of the Guidelines (e.g. “computer problems”) can also be presented.

As a more unconventional option, if the above approaches are not successful, the applicant should consider amending the specification, or even the claim itself, to explicitly specify that the computer (or its use) is an essential element of the claim. Under the Claim Language Primacy Principle, if a claim explicitly states that the computer (or processor, etc.) is an essential element, it would not be possible for a court or CIPO to rule otherwise. This suggestion is counter-intuitive, as Canadian patent agents have historically shied away from ever explicitly stating in the specification or claim that something is essential, to avoid precluding the patentee from making contrary arguments later on during litigation. However, in practice, Canadian courts tend to reject arguments of non-essentiality in the vast majority of cases. Therefore, the odds are low that the patentee will actually lose any claim scope by stating in the claim that a particular element is essential. This low risk of lost claim scope may be weighed against the greater and more immediate risk that a patent will not be granted if CIPO is not persuaded that the computer is essential.


Overall, the Guidelines are a welcome development for patent applicants. CIPO has recognized that it must assess patentability on the basis of the essential elements of the claim as purposively construed. Significantly, the Guidelines concede that if a computer is an essential element of the claim, the claim will generally be statutory. As a result, debates over patentability are expected to largely shift away from the principles of statutory subject-matter and instead focus more narrowly upon the principles of claim construction. These changes may well diminish the frequency of and costs for responding to non-statutory subject-matter objections in Canada, though these effects may take some time to materialize as CIPO further refines its approach to construction in view of applicants’ submissions.