What are Bibliometrics?
Measures of a researcher'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.
MyRi was a project between 4 Irish university libraries to produce a set of tools to support bibliometrics training. While most of it will not be of interest but just in case the homepage is here there is a very short and brief powerpoint presentation that takes some of the mystery away from bibliometrics and explains the H index..access here.
If you are interested in more information about the H Index Ann Wil Harzing of Publish and Perish Fame has a good article here