Many of you have probably already seen this. Jorge Hirsch, a physicist from UCSD, has proposed an interesting way to measure research impact of an author. For details, see this Nature article or Hirsch’s original article physics/0508025. The basic idea of Hirsh’s h-index is very simple. The index is simply the number of papers which the author has written which have more citations than this number of papers. Thus, for instance, if an author had written five papers with the following number of citations, 10, 6,4,2, and 1, then the h-index would be three because the forth most cited paper has only two citations, which is less than four, but the third most cited paper has four citations which is greater than three. The highest h-index among physicists, Hirsch claims, is Ed Witten who has an h-index of 110. This means he has written 110 papers with greater than 110 citations. Wow! Another important quantity Hirsch defines is the average rate at which an h-index has been changing per year over a career. This is just a person current h-index divided by the time since they first started publishing. Witten has an astounding value of 3.9 increase in h-index on average per year over his career. What this all means is very much open to debate, but heck, it’s kind of fun!
One thing which is nice about the h-index is it is very simple to calculate it using the ISI Web of Science citation tools or, more dangerously, from citebase. My h-index from citebase (access to Web of Science is painful from my current computer location) is 12. The funny thing is that Hirsch says that this is about the h index (with large error bars) at which one should get tenure. Haha, very funny!