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Impact factor

Last revised by Rohit Sharma on 26 Nov 2023

Impact factor is a bibliometric index. It expresses the "impact" of a publication on the reference scientific community. Specifically, it measures the average number of citations of a scientific article by other researchers.

Development of the impact factor

The impact factor was invented by an American computer scientist Eugene Garfield (1925-2017) 4 in 1955 5. Garfield is regarded as key in the development of scientometrics, the quantitative assessment of the sciences, and bibliometrics, i.e. the statistical measurement of the influence or impact that academic articles have 3,4.

In 1953, at a conference organized by the Welch Medical Library at Johns Hopkins University in Baltimore, Garfield was introduced to Shepard's Citations. Shepard's was a system employed by the legal system since 1873, measuring how American court cases cited pre-existing cases. Garfield developed the impact factor as a way to similarly track the way in which academic publications cited one another 4,5.

In 1956 Garfield founded the Institute for Scientific Information to develop the impact factor, which he later sold to Thomson Reuters Corporation, which now publishes impact factors for the scientific publishing industry.

Citation cartels

However, scientific research is not free from possible fraud. A classic example of this are the citation cartels or networks of researchers who agree to cite each other in their respective publications - regardless of the scientific value of the research - in order to grow their own citation profile by artificially increasing the H -index 6.

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