[The use of the impact index as a quality measure in research]

In this article some considerations are made upon the use of the impact factor as a measure for the quality in research. A historical view of the term "impact factor" is presented together with other aspects to keep in mind when the impact factor is used as a measure of citations. In addition, some criticisms are pointed out in the use of the impact factor as a tool to evaluate the quality of research, funding, employment and tenure.