Limitation of recall rate: The limitation of recall rate is mainly that it is the ratio of relevant information retrieved to all relevant information stored in the retrieval system, but how much relevant information in the system is generally unknown and can only be estimated.
In addition, the recall rate is more or less limited by "hypothesis", that is, the retrieved relevant information has the same value to users, but this is not the case. For users, the relevance of information is much more important than its quantity in a sense.
The evaluation of recall rate shall at least include:
(1) At the end of the preliminary investigation. After the initial retrieval is completed, it is necessary to evaluate the recall rate of the initial retrieval of the patent literature database, which is the basis for indicating whether the retrieval can be completed. If the recall rate is not ideal at this time (for example, less than 50%), it is necessary to continue the recall work, otherwise, if the expected recall rate is reached, the recall work can be ended.
(2) At the end of the denoising process. Denoising process, also known as "accurate" process, is the process of removing patent documents irrelevant to the analysis topic from the search database. In this process, the effective documents will inevitably be deleted by mistake. In order to check whether too many valid documents were deleted by mistake during denoising, it is necessary to evaluate the recall rate of patent documents after denoising at the end of the work.