Measures of a scientific writer's influence are called bibliometrics. Techniques for discerning this influence, or impact, range from simple counts of publications to sophisticated mathematical equations. Two of the most well-known bibliometrics are the impact factor, typically applied to journals, and the h-index, typically applied to authors.
What is an Impact Factor?
The impact factor, proposed by Eugene Garfield, is a ratio between citations and recent citable items published. Thus, the impact factor of a journal is calculated by dividing the number of current year citations to the source items published in that journal during the previous two years by the number of published articles in that journal during the previous two years. Journal Citation Reports calculates and publishes the annual impact factors for journals. A higher impact factor generally indicates that this journal's articles have been cited more.
What is an h-index?
The h-index was proposed by Jorge Hirsch in 2005 as an alternative to the impact factor. The h-index quantifies scientific productivity and the impact of a scientist based on the set of his/her most quoted papers and the number of citations that they have received in other people's publications. For example, an author or journal with an h-index of 30 has written at least 30 papers that have each had at least 30 citations. Thus, a higher h-index indicates more publications that have been cited more often. This metric is useful because it takes into account the uneven weight of highly cited papers or papers that have not yet been cited.
How many times have you been cited? What's your h-index?
Web of Science : Register for ResearcherID to get your bibliometric data.Futher Reading on Bibiometrics
Below is a short list of selected articles. For a more extensive list of bibliometrics articles, try searching Web of Science with search terms such as bibliometrics OR "h-index" OR "impact factor". You can also run a more limited search in PubMed by clicking here.