Published on November 7, 2012 at 11:37 PM
Various experts in bibliometrics have criticized the use of impact factor as a measure of an academic journal's visibility. A common criticism is that the indicator contains a calculation error. "Citations from all types of documents published by journal are counted," Larivière said, "but they are divided only by the number of articles and research notes. Impact factor is thus overestimated for journals that publish a good deal of editorials, letters to the editor, and science news, such as Science and Nature."
Another criticism is that the time frame in which citations are counted in calculating impact factor is too short. "There are research areas in which knowledge dissemination is faster than it is in others," Larivière said. "We cannot, for example, expect to get the same kind of impact factor in engineering and biomedical sciences." Yet journal impact factor is established in the two-year period following publication of articles regardless of the discipline.
The research results reveal some interesting points. On the one hand, journals are increasingly poor predictors of the number of citations an article can expect to receive. "Not only has the predictive power of impact factor declined, but also, impact factor is no longer suitable for evaluating research," Larivière argued. In his opinion, if we want to evaluate researchers and their work, it is best to use citations, which are a true measure of an article's impact. "This indicator is more accurate. It is not an estimation based on the hierarchy of journals." On the other hand, his work confirms that the dynamics of scholarly journals is changing, due especially to the open access of knowledge made possible by the Internet. "What then is the present function of scholarly journals?" Larivière asked. "One remains: peer review."
Source: University of Montreal