Hello all - Liz here. I know some of you have already heard about this, but a physicist at UCSD recently developed a new method of measuring the comparative "worth" of a scientist using Web of Science. It's kind of like a JCR impact factor, except it's for a scholar instead of a journal.
To search for a scholar’s h-index, go to the Web of Science and enter the name in the “General Search�
category. Clicking on “Search� brings up a list of papers over the entire lifetime by that author. To reorder the list from the most highly cited papers to least cited, click on “Sort by Times Cited� in the right hand column.
The h-index is obtained by moving down this list until the number of the paper exceeds the number of citations from that paper. For example, a scholar will have an h value of 75 whose 76 th paper on the list has been cited 75 or fewer times, but whose 75th paper has been cited 75 or more times. It's a bit confusing to read about, but give it a try in Web of Science and it's a lot more clear.
This is a new measure, so who knows what will come of it - but at least now you've heard of it if anyone asks.
Here is the citation to the paper: Hirsch, J. E. An index to quantify an individual's scientific research
output. PNAS 46:16569, Nov. 7, 2005. Link to it here (new window).
If you're interested, here's the press release from UCSD:
(From http://ucsdnews.ucsd.edu/newsrel/science/MCH.asp - retrieved 12/2/05)
November 7, 2005
UCSD Physicist Proposes New Way to Rank Scientists' Output
By Kim McDonald
Publications in peer-reviewed journals are the yardstick by which
academic scientists compare their work with their colleagues. But is
the best measure of a scientist’s worth the total number of his or her
published papers? Or the average quality of those papers, based on the
number of times they are cited or the reputation of the journals in
which they are published?
According to a physicist at the University of California, San Diego,
neither of these methods—often used in academe or federal agencies to
judge scientific publication records for hiring, promotion or grant
awards—gives consistent and satisfactory comparisons. So Jorge E.
Hirsch, a physics professor at UCSD, devised an alternative that
appears to be a simpler and more reliable way to rank scientific
output within a discipline than any now in use.
In a paper published in the November 15 issue of the Proceedings of
the National Academy of Sciences, which appears this week in the
journal’s early online edition, Hirsch explains that his “h-index� can
give a reliable “estimate of the importance, significance and broad
impact of a scientist’s cumulative research contributions.� What’s
more, for each scientist, his method provides a single number, which
takes only 30 seconds to compute, that can be used to compare a
scientist’s relative rank within a discipline.
“For a person to have a high h-index is not an accident,� Hirsch says,
after testing his method on scientists in a variety of disciplines and
circulating his formula on physics bulletin boards for other scholars
to test. “I myself was surprised to see how consistent an estimate you
get with this method. It does seem to say something about a person’s
overall academic achievement.�
The h-index is derived from the number of times a scientist’s
publications are cited in other papers, but is calculated in a way to
avoid some of the problems associated with counting large numbers of
marginal papers or high-profile coauthors.
For example, Hirsch says that while the total number of publications
gives some indication of a scientist’s productivity, it says little
about the quality of those publications. And while the total number of
times a scientist’s papers are cited in other publications says
something about their quality, he says those measurements can be
suspect if a scientist has high-performing coauthors, few publications
or a lifetime of mediocre work skewed by one or two highly cited
papers . Citation counts may also be skewed if a scientist publishes
scientific review articles, which are not reports of original
research, but summaries of other scientists’ work frequently
referenced in subsequent journal articles.
Hirsch was motivated to develop the h-index because of his own
problems publishing controversial papers on superconductivity in
journals considered high-impact. Although these papers ended up in
journals categorized as low-impact, they garnered many citations,
evidence of their importance to the field.
His new method relies on the use of the Thomson ISI Web of Science
database at http://isiknowledge.com To search for a scholar’s h-index,
go to the Web of Science and enter the name in the “General Search�
category. Clicking on “Search� brings up a list of papers over the
entire lifetime by that author. To reorder the list from the most
highly cited papers to least cited, click on “Sort by Times Cited� in
the right hand column.
The h-index is obtained by moving down this list until the number of
the paper—essentially the scholar’s h name—exceeds the number of
citations from that paper. For example, a scholar will have an h value
of 75 whose 76 th paper on the list has been cited 75 or fewer times,
but whose 75 th paper has been cited 75 or more times. Put another
way, this scholar has published 75 papers with at least 75 citations
each.
Hirsch devotes a section in his paper to demonstrate mathematically
why this method for “h�—which stands for “high citations�—seems to
work. But the real proof of the pudding came when he applied the h-
index to the scientific luminaries within various disciplines and
found that they ended up where expected.
Edward Witten, a theoretical physicist at the Institute for Advanced
Study in Princeton, N.J., who developed an extension of string theory
and is widely regarded as one of the most brilliant physicists ever,
has the highest h-index in physics, 110. By contrast, Nobel laureate
Philip Anderson of Princeton University has an h-index of 91, while
Nobel laureates Steven Weinberg of the University of Texas has an h-
index of 88, Frank Wilczek of the Massachusetts Institute of
Technology (68) and David Gross of UC Santa Barbara (66).
Hirsch, whose own h-index is 49, notes that comparisons of h-index
among scientists in different disciplines don’t work as well. High-
impact biologists tend to have generally higher h-index values, he
says, possibly because of their greater research resources, while
social scientists tend to have lower h-index values, presumably
because their other non-journal publications, such as books, are not
factored into this calculation.
Nevertheless, Hirsch is able to make some generalizations. After 20-
year career in science, he says in his paper, an h-index of 20 should
generally indicate a “successful scientist,� while an h-index of
40 “characterizes outstanding scientists, likely to be found only at
the top universities or major research laboratories.� An h-index of 60
after 20 years or 90 after a 30-year scientific career, meanwhile, he
says, “characterizes truly unique individuals.�
Hirsch says he is concerned that his h-index, while useful to compare
publication records, not be misused.
“It should only be used as one measure, not as the primary basis for
evaluating people for awards or promotion,� he adds. “You surely
wouldn’t want to say that in order to get tenure or to get into the
National Academy of Sciences you need to have an h-index of such and
such.�
Nonetheless, Hirsch’s h-index has generated intense interest among
scientists who have found out about it and used it.
“The reaction I’ve gotten has been very favorable,� he
says. “Scientists want to know how they compare to their colleagues.
The h-index really says something about that person and their work.�
Comment: Jorge Hirsch (858) 534-3931
Media Contact: Kim McDonald (858) 534-7572
Posted by biomedref at December 2, 2005 11:06 AM