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4 November 2021


On March 10, 2021, the Enlarged Board of Appeal of the European Patent Office (EPO) handed down its much-awaited decision in referral G 1/19 concerning the patentability of computer-implemented numerical simulations.

The decision will not appreciably alter the EPO’s practice concerning the patentability of computer-implemented inventions in general. However, it contains many useful hints for the applicants desirous of obtaining European patents directed to computer-implemented numerical simulations.


The questions of law answered in G 1/19 arise within the EPO’s established framework for assessing the patentability of computer-implemented inventions (points 23-26, 28-34 of the decision).

It must be recalled that the European Patent Convention (EPC), as well as French law, provides a non-exhaustive list of things and activities that are not considered as inventions, i.e. are excluded from patent protection. The established case law of the EPO has interpreted this list as a general requirement for technical character. Hence, whereas the list of “non-inventions” cites mathematical methods, programs for computers, and presentations of information, among others, the EPO considers that the exclusion actually relates to non-technical mathematical methods, non-technical programs for computers, non-technical presentations of information, etc.

In this legal framework, novelty and inventive step are assessed under the now well-established approach of the “COMVIK” decision. Under this approach, a feature-by-feature analysis of the claim must be performed in order to determine whether each feature contributes to a technical effect. Features that do not contribute to a technical effect are disregarded when assessing inventive step.

The decision’s context is limited to “simulations as such”. The Enlarged Board has understood this term to mean “a simulation process comprising only numerical input and output (irrespective of whether such numerical input/output is based on physical parameters), i.e. without interaction with external physical reality.” Therefore, only “[C]laims not including steps preceding the simulation or following the simulation” define simulations as such (point 53).

In other words, the decision places itself exclusively outside of those situations – which are known to be favorable to patentability – in which the computer outputs results which influence the functioning of some other system, such as a machine, a communications network, a graphical interface, and so forth. Quite the contrary, the question addressed by the Enlarged Board exclusively considers the simulation process and its result.


As we pointed out above, a “simulation as such” can be understood, in the words of the Enlarged Board, as “a simulation process comprising only numerical input and output. In other words, a simulation as such ultimately yields only a set of numerical values, or even a single numerical value.

In some decisions before G 1/19, a simulation as such was held to have a technical effect and therefore to be inventive under the COMVIK approach.

For instance, in T 1227/05, it was held that the simulation of a circuit subject to 1/f noise constituted an adequately defined technical purpose for a computer-implemented invention “provided that the method is functionally limited to that technical purpose”, and that accordingly, such a simulation could be considered to be a functional technical feature (point 127).

Likewise, in T 625/11, the invention was a method for establishing by a computer system at least one limit value for at least one operational parameter of a nuclear reactor, which method included a simulation step and resulted in numerical value(s) for one or more limit values for e.g. the global power P of the reactor. The deciding Board of Appeal ultimately followed T 1227/05 and held that the calculation of the operational parameter did, in the circumstances of the case, contribute to the technical character of the invention, even though the claims did not mention how the calculated operational parameter was used (points 129-130).

However, several of the reasons set forth by the Enlarged Board in G 1/19 indicate that the precedents set by T 1227/05 and T 625/11 should not be read too broadly anymore.

Indeed, the Enlarged Board indicates that “[c]alculated status information or physical properties concerning a physical object are […] mere data which can be used in many different ways. There may exist exceptional cases in which such information has an implied technical use that can be the basis for an implied technical effect. Still, in general, data about a calculated technical effect is just data, which may be used, for example, to gain scientific knowledge about a technical or natural system, to take informed decisions on protective measures or even to achieve a technical effect. The broad scope of a claim concerning the calculation of technical information with no limitation to specific technical uses would therefore routinely raise concerns with respect to the principle that the claimed subject-matter has to be a technical invention over substantially the whole scope of the claims (see point E.I.b above, referring to T 939/92)” (point 98). Accordingly, it would appear that most “simulations as such” may have few technical effects as far as input and output (which consist of data in “simulations as such”) are concerned (point 115).

The Enlarged Board mostly emphasized two types of simulation-related inventions:

i) When the technical contribution lies in the field of computing itself, e.g. implementation details concerning hardware or software (e.g., memory consumption, processing speed), the Enlarged Board does indicate that such improvements to a simulation may contribute to its technical character (points 115-116).

ii) For all other cases, e.g. when existing computation tools and methods are employed to produce an improvement in another field, the novel aspect is often not how the simulation is performed, but what is simulated. This is where the decision provides more guidance.

First of all, the decision makes a clear distinction between the simulated system and the simulation itself. The simulation itself must have has a technical effect. The fact that a technical system is simulated does not automatically fulfil this requirement (points 120 et 141).

For such inventions, the Enlarged Board considers, regarding the results of the simulation, that “[i]f the claimed process results in a set of numerical values, it depends on the further use of such data (which use can happen as a result of human intervention or automatically within a wider technical process) whether a resulting technical effect can be considered in that assessment. If such further use is not, at least implicitly, specified in the claim, it will be disregarded for this purpose (point 124).

Thus, the Enlarged Board effectively cabins the effect of T 1227/05 and T 625/11 (discussed in detail in points 127-133): The often-quoted criterion of T 1227/05 that the simulation constitutes an adequately defined technical purpose for a numerical simulation method if it is functionally limited to that purpose should not be taken as a generally applicable criterion of the COMVIK approach for computer-implemented simulations, since the findings of T 1227/05 were based on specific circumstances which do not apply in general.” (point 133).


The Enlarged Board’s approach clearly reinforces the COMVIK approach’s position as the framework for assessing the patentability of computer-implemented numerical simulations, like it already is for all other computer-implemented inventions.

Applicants should be careful not to read the precedents set by decisions such as T 1227/05 or T 625/11 too broadly anymore. Claims directed to a computer-implemented simulation will not be held to be inventive merely because they are limited to simulating a specific technical object.

A process which only involves performing a simulation, without any additional preceding or following steps, ultimately yields only a set of numerical values. Claims directed to such processes will likely held to be lack an inventive step, unless the only further use of the numerical values is technical and supports a technical effect. Moreover, the alleged technical effect should be obtained over substantially the entire scope of the claim.

In this respect, the decision distinguishes between numerical values that have a direct link with physical reality and numerical values that do not. In the first case, technical character will be generally acknowledged. For example, claims directed to a method involving taking physical measurements and then performing a simulation using the measurements are much more likely to be held to be patentable (point 99) – provided, of course, that the prior art neither anticipates such claims nor renders them obvious.

For the second case, it will be interesting to observe how the referring Board of Appeal will use the present decision to decide case T 489/14, where the simulation results are paths and dimensions in a building that only exists as a numerical model, not in reality.

For any additional information or guidance, do not hesitate to contact the undersigned:

European Patent Attorney

Jean-Baptiste THIBAUD
European Patent Attorney

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