[Strengths and weaknesses of the impact factor of scientific journals].

The impact factor is a bibliometric tool used to estimate the importance of scientific journals. It is calculated and published annually for journals indexed by the Institute for Scientific Information (ISI) and is a reflex of the average number of citations that each journal receives during a certain period of time. Since its creation it has been used as criteria in several decision-making processes such as buying journals subscriptions and submitting articles for publication.