Whether a professor wants you to cite high impact journals in an assignment or you are looking for a place to publish your work, knowing what “high impact” really means is an essential first step.

A journal’s impact factor is a measure of the frequency with which the “average article” in a journal has been cited in a particular year. It helps you evaluate a journal’s relative importance, especially when comparing it to others in the same field. The impact factor is calculated by dividing the number of current citations to articles published in the two previous years by the total number of articles published in the same period.

Although some in the scientific community have raised questions over the limited usefulness of the impact factor, the measure is still taken seriously by and large.

So which journals have a high impact factor? Thomson Scientific recently released a table ranking high impact journals in multidisciplinary sciences. Browse Thomson’s SCI-BYTES web site for journal rankings in a variety of disciplines, including robotics, statistics and others.