“Sparking” and “Igniting” Key Publications of 2020 Nobel Prize Laureates

As announced by the Royal Swedish Academy of Sciences, the 2020 Nobel Prize in Medicine was won by Harvey J. Alter, Michael Houghton, and Charles M. Rice for the discovery of the hepatitis C virus. Among the key publications reported in the scientific background (RSAS, 2020a), there are 14 articles written by at least one of the three scholars. We will introduce the characteristics of these 14 articles in detail later.

Hepatitis A and B had long been identified before researchers were able to isolate and identify the hepatitis C virus. Moreover, it has taken many years before effective antiviral medicines became available, and even now challenges remain in the form of cost and access. Contrary to the case of hepatitis A and B, there is no vaccine against hepatitis C available. Because of these facts it is no surprise that recently more articles are published related to hepatitis C, than to hepatitis A or B (Sangam et al., 2018).

The Royal Swedish Academy of Sciences awarded the Nobel Prize in Physics 2020 to Roger Penrose, Reinhard Genzel, and Andrea Ghez, for establishing the theoretical foundation of black holes and the detection of a supermassive compact object at the galactic center. Among the 54 publications of the official report (RSAS, 2020b), 19 papers were written by at least one of the three laureates above, among which, only 17 articles are of article type. Therefore, the final number of included articles in the field of physics is 17.

One of the main publications of Penrose was in collaboration with Stephen Hawking (Penrose & Hawking, 1970). Had he not died in 2018 he would have been a possible candidate for the 2020 Nobel Prize in physics.

Emmanuelle Charpentier and Jennifer A. Doudna were awarded the Nobel Prize in Chemistry 2020 for the development of a method for genome editing. There is no doubt that gene editing has been a hot topic for more than ten years. The two authors’ articles extracted from the scientific background were also published between 2011 and 2020 (RSAS, 2020c). We found that the key publications of the two laureates of the 2020 Nobel Prize in Chemistry were almost all heavily cited. They immediately ignited a huge research fire.

Because we focus on under-cited influential research, we will pay more attention to the fields of medicine and physics. We extracted data from the Web of Science including authors, titles, sources, and publication years, etc. (The latest search was done on October 29, 2020.). We then calculated the Sparking Indices using formulas (1) and (2).

Nobel Prize winners are often associated with delayed recognition (Campanario, 2009; Garfield, 1985; Gorry & Ragouet, 2019; Li & Shi, 2016) or with rejections of the first submission of their early publications (Campanario, 2009). We will not investigate these aspects in this publication. Yet, we note that Mojica (2005), a precursor of Charpentier and Doudna, who co-introduced (with Jansen) the name CRISPR, had serious problems to publish his work (Campbell, 2019). This also happened to Šikšnys, who at the same time as Charpentier and Doudna made similar observations as they did.

The six articles shown in Table 1 have a relatively low number of direct citations, respectively 302, 298, 489, 327, 322, and 527. However, their Sparking Indices S₁ are relatively high, namely two to three times the number of direct citations. A typical example is the article of Alter published in Lancet 1975, whose Sparking Index S₁ is 2.9 times that of its direct citations. In this article, Alter proposed “non-A, non-B hepatitis (NANBH)” for what we call now hepatitis C (Alter et al., 1975).

Figure 2 shows the citation network of the above article. It can be seen that the article published by Kuo et al. in 1989 received 2,999 citations, which shows that this work plays a very important role in the citation of future generations. In the same year, the article published by Choo et al. attracted greater attention and received 5,715 citations. These two examples above embody that Alter’s article in 1975 stimulates the research boom indirectly in this field. We further observe that there are many co-citations in the citation network, which indicates that there is some correlation between citing publications.

Figure 1

Figure 2

Sparking indices have been well confirmed in the fundamental work of the 2020 Nobel Prize in Medicine. Table 3 shows that among the 14 original articles of the 2020 Nobel Prize laureates in Medicine, 11 are under-cited influential papers according to our definition (Hu & Rousseau, 2016), so they are considered to be sparking fundamental work. In other words, about 79% of the original articles fall into the category of sparking fundamental work, while the remaining 21% fall into the category of igniting work.

The top 1% Sparking indices of the articles by 2020 Nobel Prize laureates in physics are listed in Table 4. An article by Penrose published in Nature-Physical Science in 1971, received 186 direct citations, but its Sparking Index S₁ is 1,743, which is more than nine times the number of direct citations. It shows that the value of this article is seriously underestimated. Figure 3 shows the citation network of this article.

Figure 3

Figure 4

As shown in Table 6, a total of 17 original literature have been collected in the field of Nobel Prize in Physics, among which 11 articles belong to the type of sparking fundamental work, sharing 68.75%, and 4 articles belong to the type of igniting fundamental work, accounting for 25%.

Unlike the fields of medicine and physics, which refer to somewhat older publications, the Nobel Prize winning articles in chemistry are published between 2011 and 2020. This phenomenon occurs partly because DNA as an important piece of genetic information was only detected in 1944 (ref), and its structure fully understood in 1953 (Watson & Crick, 1953), based on crucial information by Franklin and Gossling (1953). Then the genetic code was deciphered in 1966. All this was mainly based on the study of archaea, bacteria and viruses. In 1987 Ishino (Ishino et al., 1987) discovered the DNA sequence that would later be called CRISPR. The term CRISPR, short for clustered regularly interspaced short palindromic repeats, was not defined before 2002 (Campbell, 2019; Jansen et al., 2002), and then, finally in 2012 the CRISPPR-Cas9 technique was introduced by Charpentier and Dudna (2012), immediately (or even concurrently) leading to other fundamental work by Šikšnys, Zhang, Church, and others.

It can be seen from Table 8 that among the ten articles of this year’s Nobel Prize laureates in chemistry, nine articles are igniting fundamental work, accounting for up to 90% of the total, indicating that gene-editing technology is indeed a hot topic in recent years. Scholars also pay more attention to achievements in this field. The last remaining work is the article published by Jiang et al. in Science in 2015, which is a sparking fundamental work. But it may also turn into an igniting fundamental work with an increase in the number of direct citations because of the influence of the Nobel Prize. We note that in our previous work (Hu & Rousseau, 2016) we included (Deltcheva et al., 2011) as a sparking publication, but meanwhile it has become an igniting one, deserving mention by the Nobel Prize Committee.

By analyzing the citation history of articles of Nobel Prize laureates in 2020, we found that, if they are not “igniting” (immediate recognition by citations) they can certainly by described as sparking. This proves that the Sparking Indices truly reflect influence of the best research work. In the fields of medicine and physics, more than 68% of the articles cited by the Nobel prize Committee belongs to the group of sparking publications.

The evidence provided by our investigation suggests that Sparking Indices can be used to detect under-cited influential articles, as well as assessing fundamental work. For example, the Sparking Indices can be used as evaluation criteria for promotions, hirings, Nobel Prize winner predictions, and funding decisions.

We finally note that several factors can potentially affect the size of Sparking Indices over time, such as the topic, the publication year, the reputation of its authors, socio-political factors such as local conflicts, and so on. Further work is necessary to analyze Sparking type work in different fields and to study their possible influence on the reputation of its authors.