Experts at Clarivate’s Institute for Science Information (ISI) first began releasing a list of researchers whose work has been classed as deserving of the Nobel prize in 2002. This list of ‘citation laureates’, released a couple of weeks before the Nobel prizes are announced, is created following rigorous analysis – both qualitative and quantitative – carried out over many months to find researchers who have had their work cited 2000 times or more and who have demonstrated exceptional influence across their field and others. This year is no different and the list of 2025 citation laureates has just been released and it features scientists working on biomolecular condensates, astrochemistry and single-atom catalysis.
But what other qualitative factors do the experts at ISI consider to carry out their analysis, how long does it take and why does it feel it is important to recognise researchers in this way just a few weeks before the Nobel prizes? With the help of David Pendlebury, head of research analysis at the ISI, we answer these questions.
How is the quantitative portion of the analysis carried out?
The priority for the analysts is to look at the scientific record and identify extremely-highly cited papers, that is, papers that are cited 2000 times or more – papers that make up less than 0.02% of the literature.
The analysts go all the way back to 1970, focusing on extremely-highly cited papers from the last 10, 20 and 30 years. This, Pendlebury says, appears to be the window that the Nobel committees look at and evaluate in terms of scientific impact.
‘Only about 11,000 papers have been cited 2000 or more times since 1970 and that’s out of 64 million articles and proceedings that we review,’ he explains. ‘So, it’s a very small group of papers that have that kind of impact … and we use those citations as an indicator that the research community itself has found the work useful.’
What about the qualitative aspect?
Citation counts don’t tell the whole story, so the analysts also look at a variety of qualitative measures to narrow down the number of papers they consider.
The first of these is novelty and societal impact. The analysts will consider whether, in addition to deepening understanding of physical, chemical or biological processes, the work has made a difference in the world – the Nobel prizes’ awarding criteria states that they must be given to a researcher whose work has ‘conferred the greatest benefit to humankind’. Of course, sometimes this can take a long time to be realised – often Nobel prizes are awarded a significant amount of time after the research was carried out.
Another measure used by ISI is whether the researcher has been recognised through other prestigious awards. In chemistry, the analysts pay attention to some of the Royal Society prizes, as well as the Wolf Prize in Chemistry. Overall, there is a list of around 50 prizes which will be considered. The reason they look at this is because often there is a correlation between receipt of these prizes and subsequent awarding of a Nobel prize. ‘Sometimes people win one of these prizes after they win the Nobel, but the sequence is generally towards the Nobel prize,’ says Pendlebury.
The analysts also consider the influence of individuals’ work across other disciplines. Although of course, some work is naturally more interdisciplinary than others. ‘One of our citation laureates this year is Jean-Marie Tarascon, who’s involved in battery technology, and of course, that bridges many different areas, from material sciences to chemistry, physics and so on,’ says Pendlebury. ‘On the other hand, Anthony Hyman and Michael Rosen are focused pretty narrowly on biochemistry, so it depends.’
Finally, they consider alignment with the historical precedent of the Nobel prize. For example, many people have recognised that there is some rotation in the recognition of different subfields by the Nobel committees – for example, it is unlikely that the Nobel prize in physics would be awarded to a researcher in cosmology three years in a row.
‘In chemistry, you might have biochemistry, molecular biology and then organic chemistry, and then surface science,’ says Pendlebury. ‘There’s a rotation in recognition of subfields. Chemistry is the hardest in that regard, because there seem to be so many different niches or pockets of things to recognise.’
Pendlebury also points out that in chemistry, perhaps more than the other prizes, it’s often a methodology or tool that is recognised – for example, Crispr–Cas9 genome editing in 2020, cryo-electron microscopy in 2017 or, last year, the use of artificial intelligence in predicting protein folding.
‘Chemistry seems to be something that you could pour almost any science into,’ says Pendlebury.
How long does the process take?
Pendlebury explains that the analysis starts at the beginning of the year, but ultimately, they never really stop looking at the data. ‘We’re always seeing these very highly cited papers rising to the surface, and then we understand that we haven’t paid enough attention to them; we delve into the science itself and try to learn what we can [to] recognise its impact and the extent of its impact, and if it has these ramifications more broadly and social impact as well.’
Do the analysts consider research integrity?
Yes, the analysts will look in detail at the history of an individuals’ research contributions and look at the number of people involved in the work to ensure that there are no red flags. ‘We have our eye out for anything that may indicate a breach of research integrity,’ says Pendlebury. ‘But rarely do we find anything that we’re concerned about.’
Has the selection process changed over the years?
In general, the analysts have continued to use the same approach when selecting the citation laureates. In recent years, they have been able to apply more automation and systematic checks to the data analysis, for example, to correlate it with other prizes but the process has always been primarily quantitative with a qualitative component after that.
Do they contact the researchers to let them they know they’ve made the list?
Yes, Clarivate will reach out ahead of the announcement to let them and their institutions know. ‘They’re always delighted, usually very humble, very, very happy to get to get this kind of news,’ says Rebecca Krahenbuhl, senior manager in external communications at Clarivate. ‘It’s a delight to be able to work with them on it.’
How accurate are the citation laureates as a predictor of who will go on to win the Nobel prize?
Since 2002, Clarivate has named 465 citation laureates, of which 83 have gone on to receive Nobel prizes. However, Pendlebury says the rate of success is somewhat open ended.
‘The people who won the medicine prize last year, we named citation laureates in 2008 so they had to wait a long time. There are rare cases where the people we name win the same year, like last year, but that’s very unusual.’
However, he adds that, ultimately, they are not trying to predict Nobel prize winners but highlight researchers of Nobel class. ‘We’re trying to find the type of individual that may, in the future, win the Nobel prize. We name more people than can possibly win the Nobel prize, because, of course, there are more Nobel-class scientists than there are prizes to go around, but we still think that they deserve recognition,’ he says.
Why carry out this analysis – why not just wait for the Nobel prize to be announced?
Pendlebury explains that the history of the citation laureates goes back to the founding of the ISI by Eugene Garfield in 1960. ‘He was a pioneer in indexing the scientific literature and on the analogy of citation indexing as it was applied in the legal profession and he introduced a citation index for sciences in 1964,’ Pendlebury explains. ‘Very early on, with very little data, he asked himself the question, “different scientists show different rates of publication and citation. I wonder what the difference is between people who won the Nobel prize, and so-called ordinary scientists?”.’
In 1965, Garfield published a report that revealed that Nobel prize winners published five times as many papers and were cited 30 times as often as the average scientist. He then looked at a list of 50 of the most cited scientists in the world and found that six had already won the Nobel prize, and, after he published the list, several others then went on to win it.
Pendlebury says that looking at citations as a measure of impact within the research community is a complementary approach to traditional peer review. ‘We do this as a demonstration that citations, at least at very high frequency, are reliable signals of scientific influence and impact,’ he says. ‘It’s very important that people who are doing [literature] searches have some way to differentiate the quality and the authority of sources.’
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