T 0817/16 (Document scoring/GOOGLE) 10-01-2019

Reasons for the Decision

1. The appeal complies with the provisions referred to in Rule 101 EPC and is therefore admissible.

2. The invention

2.1 The application relates to search engines. Its background section explains that, ideally, a search engine provides the user with the results most relevant to the user's query. Relevant documents are typically identified on the basis of a comparison of the search-query terms to the words contained in the documents and other factors such as the existence of links to or from the documents. The detailed description discloses a number of techniques for scoring documents, which may be used to improve the search results returned in response to a search query.

2.2 The claimed invention is directed to the embodiment described on page 6, second full paragraph, to page 7, third full paragraph, of the published application. It proposes scoring a document on the basis of "history data" that reflects the frequency at and the amount by which the content of the document changes over time. This history data is obtained by "monitoring signatures of the document".

3. Main request - inventive step

3.1 Unlike claim 1 of the first and second auxiliary requests, claim 1 of the main request is not worded as a "computer-implemented" method and therefore arguably encompasses mental acts as such, which are excluded from patentability under Article 52(2) and (3) EPC. But since the appellant at the oral proceedings expressed its willingness to limit the claim to a "computer-implemented" method, the Board will, for the purpose of assessing inventive step, interpret claim 1 accordingly.

3.2 Since the method of claim 1 can be performed on a general-purpose computer, the Board considers such a computer to be a suitable starting point for assessing inventive step. The subject-matter of claim 1 differs from this prior art in the steps listed in claim 1.

These steps define the algorithm underlying the computer-implemented method in abstract, functional terms that do not imply any interaction with specific technical means. In particular, the step "monitoring signatures of the document" calculates and compares signatures for different versions of the document without specifying a technical mechanism by which different versions are detected or retrieved. And "generating a score for the document" and "scoring the document" merely associate the document with a calculated score value. The steps of claim 1 are thus non-technical, apart from their implementation on a computer.

It therefore has to be analysed whether, and to what extent, the steps interact with the technical feature of the claim, i.e. the feature (which the Board reads into the claim for the purpose of assessing inventive step) specifying that the method is "computer-implemented", to produce a technical effect over a general-purpose computer.

3.3 The Board concurs with the Examining Division that assigning a score to a document based on the frequency and the amount of changes to the document is not a technical task, even if performed by a computer. The appellant originally did not dispute this, but at the oral proceedings it suggested that providing good scores improved the search results returned by the search engine and that improved search results resulted in a reduction in the number of search queries, which amounted to a saving of resources.

A similar argument was dealt with in decision T 306/10 of 4 February 2015 in the context of recommendation engines. The board there considered that a reduction in the number of search queries and the corresponding saving of resources did not qualify as a technical effect of the (improved) recommendations, as they depended on subjective choices made by the user (see reasons 5.2). It referred to decision T 1741/08 of 2 August 2012, reasons 2.1.6, where the argument was made that a chain of effects cannot be used as evidence of a technical effect if one of the links between the effects is not of a technical nature (but, for example, of a psychological nature).

In the present case, the appellant's argument fails for the reason alone that claim 1 is silent on what the generated score is used for. Merely assigning a score to a document is not a technical effect. This is not different if the score is somehow based on the frequency and the amount of changes made to the document.

3.4 The appellant also argued that the method of claim 1 achieved a technical effect by implementing the task of assigning a score to a document based on the frequency and the amount of changes to the document in a particularly resource-efficient manner. Instead of storing the current version of a document in its entirety to allow the amount of changes in the next version of the document to be determined, the method of claim 1 only stored a "signature" and determined the amount of changes by comparing the signatures of the previous and new versions.

3.5 Document signatures are well known in the art but are usually suitable only for determining whether two documents differ, not for measuring the degree in which they differ. In this respect, the application, on page 7, lines 1 to 3, states the following:

"For example, search engine 125 may store 'signatures' of documents instead of the (entire) documents themselves to detect changes to document content. In this case, search engine 125 may store a term vector for a document (or page) and monitor it for relatively large changes."

The Board notes that term vectors are well known in the art. They essentially represent the content of text documents as vectors of word frequencies. Measuring the "semantic similarity" between two text documents by computing the normalised inner product of their term vectors is a standard technique. Term vectors are thus indeed suitable for determining the amount of changes between two documents or two versions of a document.

For the purpose of assessing inventive step, the Board will therefore - to the appellant's benefit - interpret "signature" narrowly as "term vector".

3.6 At least for larger documents, it is plausible that the term vector of a document takes up less memory space than the full document. But the claimed method does not achieve any savings of memory space over a general-purpose computer - which is the prior art that the Board has taken as the starting point for assessing inventive step. Indeed, performing the method of claim 1 on a general-purpose computer necessarily uses more memory resources than not performing the method. What performing the method does achieve is a particular scoring of documents, but that is not a technical effect. It also causes - like any program execution - some usage of memory and processor resources, which is at least a physical effect, but which is not a technical effect for the purpose of inventive step in so far as it does not go beyond the inherent effects of running a program on a computer (see decisions T 258/03, OJ EPO 2004, 575, reasons 5.4; T 1543/06 of 29 June 2007, reasons 2.7 and 2.8; and T 2230/10 of 3 July 2015, reasons 3.7; see also T 258/97 of 8 February 2002, reasons 6).

3.7 Nevertheless, the jurisprudence of the boards of appeal acknowledges the possibility that the design of particular non-technical method steps to be implemented on a computer has been motivated by technical considerations, in particular concerning the internal functioning of the computer, resulting in a specific technical effect being achieved when the method is run on the computer (see decisions T 258/03, reasons 5.8; T 1358/09 of 21 November 2014, reasons 5.5; and T 2330/13 of 9 May 2018, reasons 5.7.9 and 5.7.10).

According to opinion G 3/08 (OJ EPO 2011, 10), reasons 13.5 and 13.5.1, such considerations would have to go beyond "merely" finding a computer algorithm to carry out some procedure. Mere algorithmic efficiency is generally not considered to be a technical effect (see decisions T 1784/06 of 21 September 2012, reasons 3.1.2; T 42/10 of 28 February 2013, reasons 2.11; T 1370/11 of 11 March 2016, reasons 10 to 10.5; and T 2418/12 of 14 July 2017, reasons 3.3).

3.8 In the present case, the appellant's position is essentially that, in the context of a (computer-implemented) method of scoring a document on the basis of the frequency at and the amount by which the document's content changes over time, the decision to determine the frequency and the amount of changes between two versions of the document by comparing their term vectors requires technical considerations, in particular relating to memory usage.

If the appellant's point of view is correct, then that decision cannot be included in the formulation of the technical problem to be solved. Rather, it contributes to the solution of the problem of implementing a method of scoring a document on the basis of the frequency at and the amount by which the document's content changes over time in a memory-efficient manner.

3.9 According to a second point of view, determining the frequency and the amount of changes between two versions of the document by comparing their term vectors is merely an algorithmic and thus a non-technical solution to the problem of determining the frequency and the amount of changes. Although comparing document versions in their entirety may be the more straightforward solution, the degree of originality of a solution is not a criterion for technicality.

If the decision is indeed non-technical, then it can be included in the formulation of the technical problem to be solved.

3.10 As a variation on the second point of view, it could also be argued that the non-technical purpose of claim 1 is not "scoring a document on the basis of the frequency at and the amount by which the document's content changes over time" but "scoring a document on the basis of the frequency at and the amount by which the document's term vector changes over time". Indeed, a term vector, being a vector of word frequencies, is not an inherently technical object.

It is clear that the argument for the appellant and against this variation would be that this formulation of the non-technical purpose of claim 1 incorrectly hides the technicality of the decision to use term vectors in the claimed context.

3.11 Although it cannot be denied that measuring the difference between two text documents by comparing their term vectors is an algorithmic solution, this does not on its own mean that the second point of view is the correct one.

For example, in decision T 650/13 of 2 October 2018, reasons 6, this Board confirmed the holding of the older decision T 107/87 of 26 April 1991 that a data coding rule for identifying and eliminating statistical redundancy contributes to the solution of a technical problem where it is used to reduce the amount of data to be stored or transmitted. This means that if a computer-implemented method includes steps of losslessly compressing and decompressing intermediate results to reduce the amount of memory space required for storing those results, at least those steps will make a technical contribution. Still, the implementation of the coding rule will normally be algorithmic in nature.

In the Board's view, the justification for attributing a technical character to a redundancy-reducing coding rule when used for reducing the amount of data to be stored or transmitted is that such rules can fairly be said to be based on technical considerations: they would have been formulated by an engineer in the field of digital signal processing rather than by a non-technical person such as the "notional mathematician" (Article 52(2)(a) EPC) or the "notional computer programmer" (Article 52(2)(c) EPC).

3.12 More generally, the Board considers that if non-technical claim features interact with technical claim features to cause a physical effect over the prior art, such as an effect on memory usage in a general-purpose computer, the physical effect is to be regarded as a technical effect for the purpose of assessing inventive step if the non-technical features are based on technical considerations aimed at controlling that physical effect (see e.g. decisions T 2230/10, reasons 3.8; and T 2035/11 of 25 July 2014, reasons 5.2.3).

A useful test for determining whether such technical considerations are present is to ask whether the non-technical features would have been formulated by a technical person rather than by a non-technical person or persons (see e.g. decisions T 1214/09 of 18 July 2014, reasons 4.8.8; T 1321/11 of 4 August 2016, reasons 5.3.5; T 1463/11 of 29 November 2016, reasons 20 and 21; and T 136/13 of 11 September 2018, reasons 3.6). This is not an enquiry into the actual state of technical or non-technical knowledge at the effective filing date; the question is rather whether the knowledge required for coming up with the non-technical features in the particular case is of a kind that only a technical person, i.e. a person not working exclusively in areas falling under Article 52(2) EPC, could possess.

3.13 Compared with techniques for lossless data compression, it is less evident that the idea of reducing a text document to a term vector to lower memory requirements while still being able to determine the amount of changes between consecutive versions is technical. The concept of determining the semantic similarity between documents by means of term vectors belongs to the field of linguistics, which is a non-technical area falling under Article 52(2) EPC (see decisions T 121/85 of 14 March 1989, reasons 5.7; T 1177/97 of 9 July 2002, reasons 3 and 7; and T 2418/12, reasons 3.1). And the idea to use this concept in a computer program to reduce the amount of data to be stored is arguably one that the notional computer programmer would have had - more data requiring more memory being a concept inherent to computer programming.

3.14 But in the present case the Board need not make a judgment as to the technicality of the use of term vectors in the context of claim 1, as the outcome of the inventive-step assessment does not depend on it.

Accepting, for the sake of argument, the appellant's position, the objective technical problem to be solved is that of implementing, on a computer and in a memory-efficient manner, a method of scoring a document on the basis of the frequency at and the amount by which the document's content changes over time.

Starting from a general-purpose computer and faced with this problem, the skilled person would have realised that memory can be used efficiently by storing the current version of the document in a reduced form which is still suitable for measuring the difference with another document or document version. He would therefore have looked for a suitable reduced form.

At the priority date it was well known that term vectors, which the application mentions only once (in the passage cited in point 3.5 above) and without explaining it, were used for comparing the semantic content of text documents. At the oral proceedings, the appellant did not dispute this, but it argued that the invention used them for a new purpose. However, the Board judges that the skilled person would have recognised that term vectors not only were suitable for comparing text documents but also took up, at least in the case of larger documents, less memory space than the entire documents. He would therefore have chosen to store the term vector of the current document version and would so have arrived at the subject-matter of claim 1 without the exercise of inventive skill.

3.15 Hence, the subject-matter of claim 1 lacks inventive step (Article 56 EPC).

4. First auxiliary request - inventive step

4.1 Claim 1 of the first auxiliary request differs from claim 1 of the main request essentially in that it specifies that:

- a plurality of documents are monitored (but a score is generated for only one, and still on the basis of the history data obtained for that document);

- for each document of the plurality of documents, "portions of the documents that are determined to be most frequently occurring instead of [...] the entire document" are stored; and

- the score is based, at least in part, on the frequency at and the amount by which "the content of the respective stored document portion changes over time".

4.2 The wording of claim 1 suffers from a number of imprecisions.

First, the claim states that "portions of the documents" are stored for each document. But it also states that the "data relating to changes to the content of a respective stored document over time" includes a frequency at and an amount by which the content "of the respective stored document portion" changes over time. It therefore appears that, for each document, only one portion of that document is stored rather than multiple portions of multiple documents.

Second, the claim leaves undefined what is meant by "portions of the documents" (or perhaps "the portion of the document") that are (is?) "determined to be most frequently occurring". To know whether something is "most frequently occurring", it is necessary to know what kinds of occurrences are being counted. A document portion could be "most frequently occurring" within the document itself or within the plurality of documents or within a document corpus external to the claimed method (e.g. a document corpus representative of the English language).

4.3 These imprecisions cannot be easily resolved by referring to the passage of the description on page 7, lines 3 to 5, on which the amendments are based. This passage reads as follows:

"According to another implementation, search engine 125 may store and monitor a relatively small portion (e.g., a few terms) of the documents that are determined to be important or the most frequently occurring (excluding 'stop words')."

Grammatically, this sentence states that a relatively small "portion of the documents", i.e. a relatively small subset of all documents, is stored. The parenthesised qualifications "(e.g., a few terms)" and "(excluding 'stop words')" do shed doubt on this grammatical reading but do not clarify with any precision what else could be meant.

4.4 In its letter of 29 October 2018, the appellant submitted that the parenthesised qualifications "a few terms" and "stop words" did provide clarification and that a "portion" did not need to be a contiguous section of text. In view of these submissions and the above-identified imprecisions, the Board judges that claim 1 still encompasses the use of term vectors, which essentially list the most frequently occurring terms in a document and their frequencies.

4.5 The subject-matter of claim 1 of the first auxiliary request is therefore further limited compared with claim 1 of the main request as interpreted in point 3 above only in that a plurality of documents are monitored for changes. But if it is obvious to monitor a single document for changes, it is also obvious to monitor two or more documents for changes.

4.6 Thus, the subject-matter of claim 1 lacks inventive step (Article 56 EPC).

5. Second auxiliary request - inventive step

5.1 Claim 1 of the second auxiliary request adds to claim 1 of the main request essentially that a plurality of documents are monitored. As in claim 1 of the first auxiliary request, a score is generated for only one document, and still on the basis of the history data obtained for that document.

Claim 1 further makes explicit that a "signature" of each document is stored.

5.2 In point 3 above, claim 1 of the main request was already interpreted as specifying that a "signature" (or, more narrowly, a term vector) was stored for each document. The subject-matter of claim 1 of the second auxiliary request therefore lacks inventive step within the meaning of Article 56 EPC for the reason given in points 3 and 4.5 above.

6. Conclusion

Since none of the requests on file is allowable, the appeal is to be dismissed.