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My H-index: 33. April 11, 2007

Posted by dorigo in internet, news, personal, physics, science.

I learned about the existence of the H-index only a couple of weeks ago, while sharing a wedding lunch with my cousin Andrea Rinaldo, professor of Hydraulic Engineering. According to Wikipedia,

The h-index is an index for quantifying the scientific productivity of physicists and other scientists based on their publication record. It was suggested in 2005 by Jorge E. Hirsch of the University of California, San Diego.

The index is calculated based on the distribution of citations received by a given researcher’s publications. Hirsch writes:

A scientist has index h if h of his Np papers have at least h citations each, and the other (Np – h) papers have at most h citations each.

In other words, a scholar with an index of h has published h papers with at least h citations each.[1] Thus, the h-index is the result of the balance between the number of publications and the number of citations per publication. The index is designed to improve upon simpler measures such as the total number of citations or publications, to distinguish truly influential scientists from those who simply publish many papers. The index is also not affected by single papers that have many citations.

So, having learned about the crucial importance of my H-index for my career, I went on to try and find a place where I could get my own. I thus found a site which features a simple interface and tried it out.

The result ? My H-index is 33. That means I have 33 papers with at least 33 citations. Good ? Bad ? Hmmm. Wikipedia warns about comparing h-indices between scientists in different fields of research, due to differences in citation conventions. So I tried the names of a few colleagues who have been active in the last 12 years. Here is the verdict (for the years 1996-2007):

  • Dario Bisello (my boss): 35.
  • Giorgio Bellettini (the patriarch of the italian CDF community): 34.
  • Alessandro Bettini (a professor in Padova, former director of the Gran Sasso labs): 10.
  • Franco Simonetto (a professor and CMS colleague in Padova): 26.
  • Fabio Pistella (president of CNR, whose appointment has been criticized for his scarce scientific productivity ): 3.
  • Lubos Motl (a very vocal promoter of string theory and a professor in Harvard): 14.
  • Andrea Rinaldo (my cousin, director of the Department of Hydraulic Engineering in Padova): 23.
  • Edward Witten (the stellar string theorist): 68.

All in all, I think I can meaningfully say I discovered three things… First, I do not really score that bad! And second, I think the H-index is as useful in discriminating the most valuable scientists as their shoe size.

But third, and most important to me: I found out that the most cited paper I signed is “First Observation of the All-Hadronic Decay of tt Pairs“, PRL 79 (1992), 1997 - which boasts 490 citations. The exciting thing is that I did co-edit that paper – it is the one to which I directly contributed with my work as a undergraduate student and then PhD student, between 1992 and 1996 (and Patrizia, my colleague, would be unhappy if I did not mention here that the analysis was also the basis of her PhD thesis!). Something to be proud about, for once!

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1. JS - April 11, 2007

Amusing to consider papers with 499 collaborators to be your papers.

2. Andrea Giammanco - April 11, 2007

> the crucial importance of my H-index for my career

Well, maybe you should explain to the readers that the importance of the h-index for the career of an experimental particle physicist in a large collaboration is absolutely zero. The reason for this is the same reason why you discovered the existence of this index only a couple of weeks ago, and I discovered it only a few months ago (when applying to a position where I was in competition with people from other scientific fields, and the h-index was one the evaluation criteria): we sign everything, even papers we are unaware of ;)

What amazes me in your list is that Witten has such a high index even without being an experimentalist. This is the mark of a real genius, a person who has a huge impact on the whole field.
Also Lubos Motl’s ranking is quite impressive.
And of course Pistella has no excuse ;)

(Anyway, the calculator that you link, for some reason, doesn’t list my ALEPH paper… Maybe they are registered as First Name + “et al.”?)

3. dorigo - April 11, 2007

Hi Andrea,

of course I was being sarcastic when I deemed “crucial” the h-index. As you well point out, it is a measure of little relevance in our field.

Witten is the boss. His are the most cited papers in the recent history of physics. No wonder his h-index is twice as large as mine (blush)… And if you took in account all his production, not just 1996 to present, it would go above 100.

And yes, the calculator does not include many of the papers I’ve written myself… I have more than 250 publications, while the calculator only considers 120.


4. dorigo - April 11, 2007

JS, the papers are mine because I signed them off. I could have taken my name off them, or propose changes of anything I did not like.
I am honest enough to admit that I did not even read all of the papers which bear my name on them. But I did contribute a little to all – by helping taking the data on which they are based, by attending the meetings where results were being discussed and improvements were sought, by contributing to algorithms which were instrumental in measuring the quantities used for the measurements, by instructing students that later worked at the experiment themselves. By participating in the life of the experiment, that is.

If you think that is not enough to be an author, think again. Scientific achievements in high-energy physics work the way I described them, not by sitting alone at your desk with paper and pencil.


5. Kea - April 11, 2007

Well, I can only manage about h=6, but that’s all of my papers. Pretty sad, huh?

6. andy - April 12, 2007

I’m laughing at Kea because that’s my index also.

7. dorigo - April 12, 2007

Kea, Andy, theorists need not rant about small h-indices if compared to those of people participating in large experiments… The metric is quite different for experimentalists and theorists!


8. colin - April 13, 2007

Yes, Theorists have derived from string theory that it is not the size of your h-index that is truly important, it’s how you use it. And they resent the “size-ism” from the Experimental Community. ;)
(now where did i put wittens number…)

9. dorigo - April 13, 2007

Well colin,
then if the h-index is related to the length of your citation list, one should also consider a t-index, which is its thickness.

Imagine you take each of the papers citing yours, for each of your papers, and computed the average h-index of the authors of those. You would get a thickness index which is arguably even more important in determining whether a satisfactory relationship can be established with your funding agent.


10. colin - April 13, 2007

Witten agrees…

11. estraven - April 14, 2007

It’s really great of you to acknowledge that the h-index (as well as impact factor, and the like) cannot be used to compare achievement across disciplines, or across the theoretical/experimental divide.

By the way, for a mathematician it could be significant to measure the lifetime of a paper, i.e. how long it keeps getting quoted. My longest quoted is around its tenth birthday, but a senior colleague has a paper which is still regularly quoted more than 30 years after publication. I’m not sure in how many research fields this would be relevant, though.

12. Andrea Giammanco - April 14, 2007

I say it against my interest(*): any index based on publications or citations or any ratio of those quantities over author numbers, time scale of citation, etc., does not mean anything for an experimentalist in a large collaboration.
All of these are only correlated with the number of years spent in the field, and essentially NO CORRELATION exists between all those indexes and the scientific quality of a researcher.

I understand Tommaso’s point that CDF publications are by right “his own” publications. I agree, but I see it more or less like a soldier’s claim to have won a war. It may be true, but he was only a negligible part of the cause.

(*) In some competitions I ranked very well thanks to my ALEPH papers. Among which I can count the only hint so far of direct observation of the Higgs boson…

13. Coin - April 18, 2007

I think it’s a neat idea, though like all metrics it has great potential to be misleading. It shows it’s to some degree useful that it was able to pick Witten out of that list.

Still, though… exactly what is the paper database used by this H-visualizer tool? According to this thing Erdos has an h-index of 31, and Albert Einstein is at 46. I dunno about this…

14. dorigo - April 18, 2007

Yes, I think there may be problems with what that interface uses as a database. I have more than 250 papers, and it used only 110 or so.

I wonder whether there is an “official” source of h-index somewhere.


15. luca salasnich - May 25, 2007

Dear T,
it seems to me quite strange to use the h-index for people working in experimental particle physics (EPP). They write papers with more than 500 authors, and often the authors do not know the content of the papers they sign.

Hirsch is a cond-mat theoretician and the h-index
can be used to compare people working in the same sub-field of research. Surely EPP must be excluded.
In many cases the h-index can be useful.
For instance, one learns that Riotto is much better than Tonin, and Maritan (co-author
of many papers with your cousin)
is much better than G.F. Sartori.

Moreover, one learns that, usually, Italian mathematicians do not publish in serious journals and, apart some exceptions, are not quoted.

Finally, I suggest the use of the the single-author h-index, h_{sa}. That is the h-index, but considering only single-author papers.
My h_{sa} is 7. What is your?


16. dorigo - May 25, 2007

Hi Luca,

thank you for visiting here… Indeed, nobody here was proposing to use the h-index in HEP. It seems you did not read carefully the comments column, or even my original post for that matter (” I think the H-index is as useful in discriminating the most valuable scientists as their shoe size”, etc.).

As for your comparisons between people in Padova, be careful when you compare people who have given their contribution in very different time frames. Tonin worked when there was smaller diffusion of scientific papers. For the same reason, Einstein has a h-index of 46, which cannot be compared to the one of Witten because Witten is advantaged of having produced his output in a time when things are discussed much more extensively. One should, that is, “normalize” the h-index with the average number of papers published in the field during the years one’s papers were written.

7 for a single author is very good. But if you mostly work alone, you cannot compare your h_sa with those of people who have the duty of giving recognition to a group when they publish theirs.

All in all, these are all meaningless measuring sticks.


17. Luca Salasnich - September 10, 2007

Just for Prof. MM: I confirm what I have previously written here.
Plese note that mobbing is unlegal,
also in Italian departments of physics.

I confirm my idea: all university professor and reseach scientists must retire at the age of 65.
I also confirm that I do not like old (and young) theoreticians without a relevant number of single-authored papers with many citations.

18. dorigo - September 10, 2007

Hi Luca,

I fail to understand what you are referring to when you cite mobbing. It looks like you are answering to some comment made elsewhere. Or am I missing something ?


19. Signing papers « A Quantum Diaries Survivor - March 16, 2008

[...] which depends on the number of citations the paper generated. Other measures include the so-called H-index, which summarizes in a single two-digit number the scientific production of a candidate: it [...]

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