1. Determine the citation range: First of all, you need to determine a citation range, usually papers published in the last two years. This is because the impact factor needs a time window to observe the citation of the paper.
2. Count the citation times: within the citation range, count the citation times of each paper. This can be achieved by consulting various databases (such as WebofScience, Scopus, etc.). It should be noted that the number of citations here refers to the direct citation of a paper by other articles, excluding indirect citation.
3. Calculate the total citation times: add up the citation times of all papers within the citation range to get the total citation times.
4. Calculate the impact factor: the impact factor is equal to the total number of citations divided by the total number of papers within the citation range. For example, if a journal has published 100 papers in the past two years, and 50 papers have been cited at least once, then the impact factor of the journal is 50/ 100=0.5.
It should be noted that the higher the impact factor, the better. A high impact factor may mean a high publishing threshold, but it may also mean a narrow research field. Therefore, when choosing a contributing journal, we should not only pay attention to the impact factors, but also consider other factors, such as the research direction of the journal and the speed of reviewing manuscripts.