Are you a successful tweeter? Here’s how to work it out scientifically.

There is an ongoing debate about how best to measure research performance, if indeed it can be measured, and if the measurements actually mean anything. I have had my fair say on this, and argue that, because of the way that science works in practice, we need to be funding diverse networks of science, since the most important advances generally come from unexpected quarters (see my TV Interview: “We need to fund diverse networks of science” (

Be that as it may, employers and funders face a real problem in comparing individual scientists with each other. To get round the problem, the physicist Jorge Hirsch suggested in 2005 that each researcher should be given an “index” (now called an “h-index”), based on how often his or her papers are cited by others. According to Hirsch:

“A scientist has an index h if h of his or her Np papers have at least h citations each, while the other (Nph) papers have no more than h citations each.”

You can see from the unnecessary introduction of the symbol Np into the discussion that Hirsch is a theoretical physicist. In practical terms, all one needs to do is to label one’s papers 1, 2, 3 .. etc in descending order of the number of citations, and write the number of citations against each one. When the two lists of numbers (the number of the paper, and the number of citations) cross over, that’s the h-index.

Despite its many problems (variability between fields, effect of age of researcher, identifying all relevant papers when authors sometimes use initials and sometimes their full names), this measure has been quite widely used since its introduction. It occurs to me that we could use a similar measure in the Twittersphere to identify the Tweeters who are having the most impact, simply by listing our tweets in descending order of the number of re-tweets, and identifying the crossover point just as with the h-index.

Since the h-index is named after its originator, I would like this index to be named after me and, despite the double entendre, I humbly suggest that it be called the f-index.

I wonder how many times this idea will be re-tweeted?

Len Fisher (h-index = 26; f-index = 8)

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