A colleague (who possibly should get out more) has been carrying out an analysis of the H-Index of staff in the top rated UK Materials Science departments. There is a very strong correlation between length of service and H-Index, and an interesting similarity in the gradient of the regression between the departments. More statistical analysis is in progress to compare disciplines and countries. Watch this space for further revelations.
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Title to be Announced by Brian Derby
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H-Index Analysis
- Date:
- Friday, 12 Sep tember 2008 - 09:01 UTC
Last updated: Friday, 12 Sep 2008 - 09:01 UTC
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Comments
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Thank you, Brian. I hope you don’t mind, but I have cross-posted this at the Citation in Science forum as I expect that group will be very interested in this study and the “further revelations”.
The correlation between length of service and H-index is pretty much inevitable, given that papers in many journals have “citation half lives” in the orders of several years (e.g. 7-8 yrs for some journals in my field of physiology).
I would be interested to know if this levels off:
“Your H-index asymptotically approaches its “final representative figure” as your (n years in the business) increases towards _x_"
…where x = say 20-30
…Or just keeps on rising.
More evidence, of course, that bibliometrics and citation-o-metrics are not exact science. A particularly damning view can be found here.
Austin – Our initial analysis seems to show the opposite. Younger appointees have highe normalised h-indices. this might indicate that many papers reach a saturation citation level at a low level and only a few take off.
That’s interesting, Brian. Normalised how?
..also depends what you call “low”. I am grateful for anything on my CV that crawls it’s way to > 15 citations after a few years on PubMed…!
When I ran my H-index, and that of a few of my colleagues, a year or so back I had the impression that the dominant factor was how many papers were cited > 20 (or > 30 or > 40) but < 60-70 times, i.e the “middle range” was the key. I was thinking this would relate to both “body of work” and “length of service” (as well as to quality of the work).
One would have thought that just having a few highly cited papers wouldn’t make a difference – e.g. if you have four papers cited > 200 times, six more cited between 10 and 20 times, and two cited < 10 times, as I understood it your overall H-index was still only 10.
Actually I thought the selling point of H-index was specifically supposed to be its reflection of “body of reasonably well cited work” rather than either “large volume of work that is almost never cited” or “one or two super-cited papers only”.
Of course, this may all reflect different citation patterns in different fields. In the biosciences there are a lot of journals with “Impact Factors” of less than 1.0. So there must be many papers that never get cited at all. I recall a former Dean of mine who used to exhort us regularly with the line:
“Ask yourselves: do you publish in one of the top two hundred biological science journals? Or in one of the bottom two thousand?”
It’s hard to see the reason for starting this discussion before anyone can see the results.
In the absence of results, all I can say is that I agree that you friend should get out more. Since the H-index is obviously one of the more bone-headed of various suggestions that have been made for surrogate endpoints (as they’d be called in a clinical trial) perhaps it might be a good idea to do some science rather than spending time on things that damage science.
Ouch!
I’m feeling sheepish now, David. I will only say that my computing my own H-index was prompted by a senior Professor in my own locality telling me that another (and even more senior and eminent) Professor had asked him “have you worked out your H-index yet?”.
The worry is that, if one believes the whispers from the corridors of power and/or leaks from RAE HQ, the “light touch” version to replace the current labour-intensive RAE set-up is almost certain to involve some kind of “surrogate endpoint(s)” of the publication metric variety.
No need for “ouch”. That wasn’t aimed at you but at the “senior and eminent” professor who wasted your time with it. I won’t ask you who it was (not here anyway).
Of course you are quite right that the REF is worrying. We all will have to waste yet more time keeping an eye on what they are doing (not science for sure).