Should highly cited items be excluded in impact factor calculation? The effect of review articles on journal impact factor

The use of the journal impact factor for evaluation purposes has been widely challenged because of the simplistic algorithm involved in impact factor calculation. As a result, a journal's impact factor may be affected by many variables, such as highly cited review articles. In the present study, we aimed to investigate whether and to what extent review articles affect the impact factors of journals. We examined the citations of original research articles and review articles in the field of physics, and compared the impact factors of the journals Science, Nature, and Cell with and without citation counts of review articles included. The results showed that review articles consistently received higher numbers of citations than did original research articles. In addition, review articles accounted for 3–10% of the impact factors of these top journals. Based on our findings, we suggest that sophisticated methods, in addition to the impact factor, be employed for research evaluation purposes.