1. First, you need to get the full text of the paper and a list of references. This information can usually be obtained from academic databases, periodical websites or authors' personal homepages.
2. Check the list of references one by one and find out all the cited documents. If the author of a document is the same as the author of the current paper, then the document is considered to be self-quoted.
3. Count the number of self-cited documents. This can be achieved by calculating the proportion of self-cited documents in the total references. For example, if the total number of references is 100, and 5 of them are self-cited, the self-citation rate is 5%.
4. In order to ensure the accuracy of the results, the above steps can be repeated many times to eliminate random errors. In addition, it can be compared with other researchers' results to ensure the consistency of self-citation rate.
It should be noted that the self-citation rate of a paper is not the only criterion to measure the quality of a paper. In fact, moderate self-citation is acceptable because it can help the author to establish his own research system and theoretical framework. However, the high self-citation rate may make readers question that the author relies too much on his own research results and lacks full understanding and critical thinking about other studies. Therefore, when writing a paper, we should properly control the proportion of self-citation and pay attention to citing other related studies to improve the academic value and readability of the paper.