The h-index is an index that attempts to measure both the productivity and impact of the published work of a scientist or scholar. The index is based on the set of the scientist's most cited papers and the number of citations that they have received in other publications. The index can also be applied to the productivity and impact of a group of scientists, such as a department or university or country. The index was suggested by Jorge E. Hirsch, a physicist at UCSD, as a tool for determining theoretical physicists' relative quality and is sometimes called the Hirsch index or Hirsch number. (source: http://en.wikipedia.org/wiki/H-index).
Data source: SCImago. (2007). SJR — SCImago Journal & Country Rank. Retrieved December 27, 2011, from http://www.scimagojr.com