The Citation Culture

The widespread use of rankings of journals in research institutes and universities creates a disadvantage for interdisciplinary research in assessment exercises such as the British Research Excellence Framework. This is the conclusion of a paper presented at the 2011 Annual Conference of the Society for the Social Studies of Science in Cleveland (US) by Ismael Rafols (SPRU, Sussex University), Loet Leydesdorff (University of Amsterdam) and Alice O’Hare, Paul Nightingale and Andy Stirling (all SPRU, Sussex University). The study is the first quantitative proof that researchers working at the boundaries between different research fields may be disadvantaged compared with monodisciplinary colleagues. The study argues that citation analysis, if properly applied, is a better measurement instrument than a ranked journal list.

The study is quite relevant for research management at universities and research institutes. Journal lists have become a very popular management tool. In a lot of departments, researchers are obliged to publish in a limited set of journals. Some departments, for example in economics, have even been reorganized on the basis of having published in such a list. The way these lists have been composed does vary. Sometimes a group of experts decides whether a journal belongs to the list, sometimes the Journal Impact Factor published by ISI/Thomson Reuters is the determining factor.

The study by Rafols et al. has analyzed one such list: the ranked journal list used by the British Association of Business Schools. This list is based on a mix of citation statistics and peer review. It ranks scholarly journals in business and management studies in five categories. “Modest standard journals” are category 1, “world elite journals” are category 4*. This scheme reflects the experience researchers have with the Research Assessment Exercise categories. The ranked journal list is meant to be used widely for a variety of management goals. It is used as an advice for researchers about the best venue for their manuscripts. Libraries are supposed to use it in their acquisition policies. And last but not least, it is used in research assessments and personnel evaluations. Although the actual use of the list is an interesting research topic in itself, we can safely assume that it has had a serious impact on the researchers in the British business schools community.

The study shows first of all that the position of a journal in the ranked list correlates negatively with the extent of interdisciplinarity of the journal. In other words, the higher the ranking, the more narrow its disciplinary focus. (The study has used a number of indicators for interdisciplinarity by which different aspects of what it means to be interdisciplinary have been captured.) Rewarding researchers to publish first of all in the ranked journal list may therefore discourage interdisciplinary work.

The study confirms this effect by comparing business and management studies to innovation studies. Both fields are subjected to the same evaluation regime in the Research Excellence Framework. Intellectually, they are very close. However, they differ markedly with respect to their interdisciplinary nature. Researchers in business schools have a more traditional publishing behaviour than their innovation studies colleagues. The research units in innnovation studies are consistently more interdisciplinary than the business and management schools.

Of course, publication behaviour is shaped by a variety of influences. Peer review may be biased against interdisciplinary work because it is more difficult to assess its quality. Many top journals are not eager to publish interdisciplinary work. This study is the first to show convincingly that these already existing biases tend to be made even stronger by the use of ranked journal lists as a tool in research management. The study confirms this effect by comparing the performance based on the ranked journal list with a citation analysis. In the latter, the innovation studies research is not punished by its more interdisciplinary character which does happen in an assessment on the basis of the journal list. The paper concludes with a discussion of the negative implications in terms of funding and acquiring resources for research groups working at the boundaries of different fields.

The paper will be published in a forthcoming issue of Research Policy and has been awarded the best paper at the Atlanta Conference on Science and Innovation Policy in September 2011.

Reference: Ismael Rafols, Loet Leydesdorff, Alice O'Hare, Paul Nightingale, & Andy Stirling, “How journal rankings can suppress interdisciplinary research. A comparison between innovation studies and business & management,” Paper presented at the Annual Meeting of the Society for the Social Studies of Science (4S), Cleveland, OH, Nov. 2011; available at http://arxiv.org/abs/1105.1227.

Recently, the new Times Higher Education World University Rankings 2011-2012 saw the light. The ranking revealed that Harvard University is no longer number one on the list. Incidentally, the differences with Caltech - now highest - are minimal. The main reason for Caltech’s rise are the extra revenues it drew out of industry. Caltech’s income increased by 16%, thereby outclassing most other universities. Harvard scored a bit better when it comes to the educational environment. Other universities also rose on the list as a result of a successful campaign to obtain (more) external financing. The London School of Economics, for example, moved from 86 to 47. The top of the ranking did not change that drastically though. Rich US-based universities still dominate the list. 7 out of ten universities highest on the list, and one third of the top 200, are located in the US.

This illustrates the THE ranking’s sensitivity to slight differences between indicators that, taken together, shape the order of the ranking. The ranking is based on a mix of many different indicators. There is no standardized way to combine these indicators, and therefore there inevitably is a certain arbitrariness to the process. In addition, the THE ranking is partly based on results of a global survey. This survey invites researchers and professors to assess the reputation of universities. One of the unwanted effects of this method is that well-known universities are more likely to be positively assessed than less popular universities. Highly visible forms of maltreatment and scandals may also influence survey results.

This year, the ranking’s sensitivity to the ways in which different indicators are combined is aptly illustrated by the position of the Dutch universities. The Netherlands are at number 3, with 12 universities in the top 200 and 4 in the first 100 of the world. Given the size of the country, this is a remarkable achievement. The result is partly caused by a strong international orientation of the Dutch universities, and partly by previous investments in research and education. But just as important is the weight given to the performances of the social sciences and humanities in a number of indicators. Compared to last year, the total performance of Dutch universities most likely did not increase that much. A more likely explanation is that the profile of activities and impact are better covered by the THE ranking.

The latest THE ranking does make clear that size is not the most important determinant in positioning universities. Small specialized universities can end up quite high on the list.

“My research: > 185 papers, h-index 40.” A random quote from a curriculum vitae in the World Wide Web. Sometimes, researchers love their Hirsch index, better known as the h-index. But what does the measure actually mean? Is it a reliable indicator of scientific impact?

Our colleagues Ludo Waltman and Nees Jan van Eck have studied the mathematical and statistical properties of the h-index. Their conclusion: the h-index can produce inconsistent results. For this reason, it is actually not the reliable measure of scientific impact that most users think it is. As a leading scientometric institute, we have therefore published the advice to all universities, funders, and academies of science to abandon the use of the h-index as a measure of the overall scientific impact of researchers or research groups. There are better alternatives. The paper by Waltman and Van Eck is now available as a preprint and will soon be published by the Journal of the American Society for Information Science and Technology JASIST.

The h-index is a measure of a combination of productivity and citation impact. It is calculated by ordering the number of publications by a particular researcher on the basis of the total number of citations they have received. For example, someone who has an h-index of 40 has published at least 40 articles that have each been cited at least 40 times. Moreover, the remaining articles have not been cited more than 40 times each. The higher the h-index the better.

The h-index was proposed by physicist Jorge Hirsch in 2005. It was an immediate hit. Nowadays, there are about 40 variants of the h-index. About one quarter of all articles published in the main scientometric journals have cited Hirsch’ article in which he describes the h-index. Even more important has been the response by scientific researchers using the h-index. The h-index has many fans, especially in the fields that exchange many citations, such as the biomedical sciences. The h-index is almost irrresistable because it seems to enable a simple comparison of the scientific impact of different researchers. Many institutions have been seduced by the siren call of the h-index. For example, the Royal Netherlands Academy of Arts and Sciences (KNAW) in the Netherlands inquires about the value of the h-index in its recent forms for new members. Individual researchers can look up their h-index based on Google Scholar documents via Harzing’s website publish or perish. Both economists and computer scientists have produced a ranking of their field based on the h-index.

Our colleagues Waltman and Van Eck have now shown that the h-index has some fatal shortcomings. For example, if two researchers with a different h-index co-author a paper together, it may lead to a reversal of their position in an h-index based ranking. The same may happen when we compare research groups. Suppose we have two groups and each member of group A has a higher h-index than a paired researcher in group B. We would now expect that the h-index of group A as group is also higher than that of group B. Well, that does not have to be the case. Please note that we are now speaking of a calculation of the h-index based on a complete and reliable record of documents and citations. The problematic nature of the data if one uses Google Scholar as data source is a different matter. So, even when we have complete and accurate data, the h-index may produce inconsistent results. Surely, this is not what one wants using the index for evaluation purposes!

At CWTS, we have therefore drawn the conclusion that the h-index should not be used as measure of scientific impact in the context of research evaluation.

Two weeks before the start of the 2011 academic season, the latest issue of the Academic Ranking of World Universities (ARWU) was published. The response to this ranking in the Netherlands is telling about the importance ascribed to global university rankings. Utrecht University saw its position improved with 2 points and went to number 48. Leiden University went up 15 points and is now second after Utrecht at number 65. All Dutch universities are now listed among the 500 “best universities” in the world. The organization of Dutch universities VSNU was thrilled. This was an “excellent performance”, according to the organization, because “the Shanghai Ranking is in itself already a selection of the five hundred best universities in the world. This means that the Dutch universities belong to the best 3 percent of the total universities in the world (17,000).” In our view, this shows that the VSNU has not really understood the point of this ranking and the rationales behind its construction.

All measurements are preceded by decisions pertaining to the object(s) and focus of measurement. In this categorization process, certain factors will be labeled as relevant and others as less or irrelevant. Decisions will be made pertaining to the parameters of the categories that will be taken into account. These decisions fundamentally shape the subsequent measurements. The ARWU ranking is based on the data of 1,000 universities (the other 16,000 are not taken into account). The ranking strongly favours large universities. Because Nobel Prizes and Field Medals have a strong impact on the total ranking, and other prestigious prizes are not taken into account, the ARWU advantages Anglo-Saxon universities and the universities focused on the exact and medical sciences. From its beginning in 2003, the ARWU ranking is led by US universities, with Harvard as number one. The only non-US universities among the top ten are Oxford and Cambridge.

The way research performance is measured in the Shanghai ranking is also problematic. The number of articles in the journals Nature and Science determine 20 % of the ranking score, but prestigious monodisciplinary journals such as Cell or Physica Acta do not weigh so heavily. Influential humanities researchers are almost invisible in the ranking. Just before the Summer, the European University Association pointed to the disadvantages of the most popular global university rankings. In fact, they only rank the elite of the international university system. Moreover, composite rankings like the Shanghai Ranking merge different aspects of university performance (research, teaching, valorization, social impact) into one number. How this composite number is calculated is rather arbitrary and not always transparent. It is therefore unclear to what extent a change in position has anything to do with change in performance.

For example, it is quite certain that the small improvement of Utrecht University is a fluctuation without any significance. Additionally, even a seemingly robust improvement of the performance of a university can be caused by an individual outlier. According to the website Transfer, the three Dutch universities that saw their position most strongly improved had three individual researchers to thank for this improvement. Radboud University went up thanks to Nobel Prize winner Konstantin Novoselov. Eindhoven’s technical university should send flowers to computer scientist Wil van der Aalst, and Maastricht has risen thanks to behavioural psychologist Gerjo Kok. The fact that individual researchers can have such a strong influence on the position of a university in this ranking may trigger all sorts of perverse behaviour, such as trying to lure staff away from a competing university.

Rafael Wittek, director of the Internuniversity Center for Social Science Theory and Methodology, based at the University of Groningen, recently attacked Dutch university policies at the occasion of the 25^th anniversary of his famous graduate school. One of his targets was “the hype around rankings”. Accredited in 1986, the ICS was the first national social science graduate school in the Netherlands. The school emerged from Dutch networks of PhD students that were funded by the Ministry of Education and Science. According to Wittek, the universities are now trying to get a high score in the global rankings (such as the Times Higher Education ranking, the Shanghai ranking and of course also the Leiden ranking) and he argued that this is a wrongheaded approach. “Rankings as an indicator of quality are a hype. To adopt them is merely a policy reflex.”

I think the sociologist puts his finger on a sore spot in Dutch science policy and management. This is particularly true for his critique of the policies around PhD training and the national Graduate Schools. According to Wittek, “The Hague” has been too eager to follow new European guidelines and has promoted the competition, rather than the cooperation, among universities. “In the last couple of years, many national Graduate Schools have been dismantled and new local Graduate Schools have been created in their stead. Dutch universities increasingly claim the results of ‘their’ researchers and give them less possibilities to collaborate with colleagues from other universities”. His remarks will strike a chord with everybody (such as myself) who have been formed in the national research schools in which all or almost all universities worked together. It is indeed a loss that the Dutch ministry discouraged national Graduate Schools and completely switched towards stimulating local ones, although happily a few nation-wide schools are still alive and kicking (such as the Graduate School Science, Technology and Modern Culture).

Still, although his remarks are to the point, I do not think he is completely right. For example, it is simply not true that the Dutch universities would be involved in a ruthless competition with each other. On the contrary, the new trend is the emergence of regional clusters of universities as a new form of intimate collaboration to be able to compete globally with American and Asian universities. Increasing collaboration is moreover the trend in scientific publications, as demonstrated recently by a study of my colleagues at CWTS and by the recent Royal Society Report on scientific networks. The share of the multi-authored, multi-institutional, international publications is still rising, in all fields of research. And their average citation impact is greater than those of single-author or national publications. I don’t think that we should overestimate the power of university boards to limit the scale of scientific collaboration.

Nonetheless, Wittek’s criticism of ranking should certainly be taken very seriously. The sociologist sees a danger in the “policy reflex” for the quality of research and in particular in the areas of high-risk fundamental research. He thinks that researchers who are forced to score high in the rankings will be reluctant to take on big, important questions and will tend to develop a more limited and less risky research agenda. I agree. This is indeed the most important risk of rankings running wild, disconnected from the context of fundamental or applied research. But I think there may be a bit more at play than just policy reflexes. The universities are confronted with an accelerating process of global competition in which new scientific centres are emerging, among others China, India, Brazil, Turkey and Iran. In these countries, researchers tend to have to meet much stricter performance criteria than is usual in the Netherlands. This makes it difficult, perhaps even impossible, for Dutch university boards to ignore this. In the Netherlands this problem is particularly acute since the recent xenophobic hype around immigration in this country is making it already difficult enough to attract talented young researchers from non-European countries. Does this mean that an obsession with rankings is inevitable? I think not. I could imagine a number of alternative, more imaginative strategies to counter this race for the highest position in the rankings.

I do think Wittek is right that recognition by peers is the strongest motivator for researchers. He even thinks that scientists do not need any other stimulus. This last idea may be a bit over the top. But I do think he has a good point. Therefore, rankings can and should be used in direct connection with this peer stimulus. Policies that are only focused on getting higher in the global university rankings indeed do not make much sense. But this does not mean that it makes no sense at all to rank. Rankings can very well be used to get a better understanding of ones strong and weak points (both at the level of individual researchers, groups and institutes, and universities and countries). This can be done while taking into account the specific characteristics of the relevant disciplines. (For different disciplines different databases may be needed to measure the rankings). Ranking in context, that should be possible, shouldn’t it?