A novel approach to measuring patent claim scope based on probabilities obtained from (large) language models

This work proposes to measure the scope of a patent claim as the reciprocal of the self-information contained in this claim. Grounded in information theory, this approach is based on the assumption that a rare concept is more informative than a usual concept, inasmuch as it is more surprising. The self-information is calculated from the probability of occurrence of that claim, where the probability is calculated in accordance with a language model. Five language models are considered, ranging from the simplest models (each word or character is drawn from a uniform distribution) to intermediate models (using average word or character frequencies), to a large language model (GPT2). Interestingly, the simplest language models reduce the scope measure to the reciprocal of the word or character count, a metric already used in previous works. Application is made to nine series of patent claims directed to distinct inventions, where the claims in each series have a gradually decreasing scope. The performance of the language models is then assessed with respect to several ad hoc tests. The more sophisticated the model, the better the results. The GPT2 model outperforms models based on word and character frequencies, which are themselves ahead of models based on word and character counts.