The logical OR is used to provide recall.
A and B: have the contents of both A and B; A or B: the first case is only A; the second case is only B; the third case is both A, B. Therefore, using "logical AND" can narrow the search scope, and using "logical OR" can expand the search scope.
Extended information:
The evaluation of recall rate at least includes:
①At the end of the preliminary recall. When the preliminary search work is completed, the recall rate of the preliminary search patent document database must be evaluated. This recall rate is the basis for indicating whether the search work can be completed. If the recall rate is not ideal at this time (for example, less than 50%), the recall work needs to continue. On the contrary, if the expected recall rate is reached, the recall work can be ended.
②At the end of the denoising process. The denoising process is also called the "accurate search" process. It is the process of removing patent documents that have nothing to do with the analysis subject from the search database. In this process, valid documents are inevitably deleted by mistake. In order to check whether the denoising process is Too many valid documents were mistakenly deleted. At the end of the denoising work, the recall rate of the denoised patent document collection must be evaluated.
Baidu Encyclopedia - Logical AND
Baidu Encyclopedia - Recall Rate