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June 26, 2020 at 13h44
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Einstein is it worth half of Dr. Raoult ? To end with the “index h”
Yves Gingras
Professor, UQAM
Mahdi Khelfaoui
Associate professor, UQAM
THE SCIENCE IN HIS WORDS / The media controversies surrounding professor Didier Raoult provides the opportunity to get back on the ubiquitous index bibliometric h-index, invented in 2005 by the american physicist John Hirsch (hence the choice of the letter “h” to refer to the index).
The”h index” or “factor h”, French has become in the space of a few years an indispensable reference for many researchers and managers of the academic world.
It is especially promoted and used in the biomedical sciences, a field in which the mass of publications seems to have made it impossible to any qualitative assessment of a serious work of researchers. This “indicator” has become the “smoke and mirrors of assessment”, in front of which the researchers admire or chuckle by noting the pitiful “h index” of their “dear colleagues”, but still rivals.
Although experts in bibliometrics have quickly noted the dubious nature of this composite indicator, most researchers do not always seem to understand that its properties are far from making a index is valid to assess seriously and ethically their “quality” or “impact” of science.
Most often, its promoters commit a mistake of elementary logic, saying that the Nobel prize winners “in general” an h-index high, evidence that it measures the quality of individual researchers. However, if an h-index may indeed be associated with a Nobel, this is not proof that an h-index high-bit is not necessarily associated with a “poor” researcher. In effect, an h-index seemingly weak can hide a scientific impact higher, at least if one accepts that the standard unit for this scientific visibility is reflected in the number of citations received.
The limitations of the h index
Defined as the number of articles of an author that have each received at least N citations, we immediately see that this index is bounded by the total number of items. In other words, if a person has twenty papers that are cited a hundred times each, her h-index is 20, just as a person who also has twenty articles, but cited each only twenty times, five times less ! But any serious seeker would say that the two are “equal” to the fact that their h-index is the same ? However, if an indicator is not proportional to the concept that it is supposed to measure, then it is invalid.
The most ironic thing in the history of the h-index is that its inventor was originally designed to counter the use of the number of papers, which according to him did not well reflect the scientific impact of a scientist. He thought, therefore, the “correct” combined with the number of citations that the articles receive. Worse, it turns out that the h index is in fact very highly correlated (up to the height of about 0.9) with the number of publications ! In other words, it is indeed the number of publications increase the h-index more than the number of citations, an indicator, which, despite its limitations, remains the best measure of the impact of scientific publications.
Library The Sun
All this is known to experts, but may not be researchers, evaluators and journalists who allow themselves to be impressed by the characters parading with their h-index is stuck to the front.
Raoult vs Einstein
In a recent survey of Médiapart, a researcher part of the evaluation committee of the laboratory of Dr. Raoult, told the journalist not to be left to impress : “The thing that struck me, she said, it is the obsession to Didier Raoult for his publications. A few minutes prior to the start of the valuation of its unit, that is the first thing he showed me on his computer, his factor h.”
Dr. Raoult had himself asserted in 2015 in the magazine Le Point that he had to “count the number and impact of publications of the researchers to assess the quality of their work”. So let’s look at the famous “factor h,” Dr. Raoult and look at how it compares, say, with that of a researcher who is widely regarded as the greatest scientist of the last century : Albert Einstein.
In the database Web of Science (WoS), Didier Raoult account 2053 articles published between 1979 and 2018, having received a total of 72 847 citations. Her h index calculated from these two data is 120. However, it is known that the value of the h-index can be inflated artificially due to the citations made by an author in his own articles, what is known of the autocitations. However, the WoS shows that among the citations, the total awarded to articles co-signed by Didier Raoult, 18 145 from articles of which it is legally co-signer, which is equivalent to a rate of autocitations of 25 %. Ignoring these autocitations, the h-index of Raoult decrease of 13 % to a value of 104.
Now we’ll look at the case of Albert Einstein. The latter comprises 147 articles identified by the WoS between 1901 and 1955, the year of his death, for a total of 1564 citations received in his lifetime. On these 1564 citations, only 27, is a meagre 1.7 per cent, are of the autocitations. If one adds the citations to his articles after his death, Einstein received a total of 28 404 citations between 1901 and 2019. From these data on publications and citations, Einstein obtains an h-index of 56.
If we must rely to the extent so called “objective” of the h-index, one is then forced to conclude that the work of Didier Raoult, with its corrected index of 104, has an impact and reach of scientific two times larger than those of the father of the photon, of relativities, restricted and general, of the Bose-Einstein condensation and of the phenomenon of stimulated emission to the origin of the lasers. Perhaps it is better to conclude, as suggested above, that the indicator is simply bogus ?
Also note the significant difference in the number of citations the total received by each of the researchers in the course of their career. They have obviously been active in very different times, the size of the scientific communities, and therefore the number of potential authors quoting it, has increased dramatically over the last half-century. It is also necessary to take account of differences in disciplinary and collaborative practice. For example, the theoretical physics are far fewer contributors as microbiology, as well as the number of co-authors per article is smaller, which influences the “productivity” and the measure of the impact of researchers and makes use of the comparative of the h-index more than problematic.
Finally, it is important to note that the statement : “The index h of the person P is X”, has in fact no meaning, because the value of the index depends on the contents of the database used. It should rather say “The index h of the person P is X, in the database Z”. Thus, according to the database WoS, which contains only journals considered to be serious and quite visible in the scientific field, the h-index of Didier Raoult is 120. By contrast, in the free database and therefore easily accessible from Google Scholar, which contains all sorts of heterogeneous documents, including pdf documents filed on various sites on the Internet, the same index h — picked up by most of the media rises to 179.
The fetishism of a figure
The scientific community devotes a real cult to the index in h. And this fetish for a simple figure can have negative consequences for scientific research. France, for example, uses the System to query, management and analysis of scientific publications (SIGAPS) for grant funds research in its laboratories of biomedical sciences, on the basis of the number of articles they publish in the magazines say “high impact factor”. As reported by Le Parisien, the frenetic pace of publications of Dr. Raoult allows the institution to reap between 3 600 and 14 400 euros per year, for each article published by his team.
The blindness caused by the deviation of the evaluation of the research is interesting and would require studies on the psychology of researchers. The biologist Bruno Lemaître, published an illuminating book on the narcissism of researchers. It would perhaps be necessary to complete this study by an analysis of the syndrome of brain split, resulting from the disconnection between the two hemispheres of the brain : capable of detecting minor errors in the publications of their colleagues, many researchers seem helpless when confronted with the distortions created by their “smoke and mirrors of assessment”.
The good uses of bibliometrics, or even simple common sense, should teach us to be wary of the indicators are simplistic and one-dimensional. Slow down the pace maddening of scientific publications — often of limited usefulness outside of the filling of the CV academic — would certainly the researchers to lose interest in the index h. More important, it would contribute to produce knowledge, certainly less numerous, but certainly more robust.
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This text is first published on the website of the franco-canadian of The Conversation. Reproduced with permission.
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