The impact factor is defined as "the ratio of the total number of citing articles/papers to the total number of published papers/articles in a journal per year". So here is my question. Why don't we have impact factor for individual articles? for example, if a journal, let say, PHYSCOM, has published 100 articles in 2014 and they were cited 222 times, its impact factor is 2.22. let say an article AA cited in the same journal 100 times, where as many articles are never cited at all, then why both types of articles (highly cited and non-cited) are equal with the same impact factor? Please discuss